Don't forget, this coming Sunday (June 21st) is your chance to come along and inspect the RRRG project at close quarters! See how we are getting on, chat to the team, find out how the money is being spent, discuss what we still need to do and how we plan to go about doing it! Have a guided tour of the locomotives and the RRRG infrastructure. Maybe find out how you could get involved? Get your RRRG branded merchandise from our sales stand! All this from 2 PM onwards at our Rowsley South, Peak Rail base, just off the A6 north of Darley Dale. As it happens there is a vintage bus rally at Peak Rail that same day so you can just follow the crowds to find us!
This article came about after a discussion between myself and Dom Jackson, and is intended to give an idea of the difficulties and problems faced during rebuilding of the electrical cubicle in 50030 Repulse.
When we acquired The Twins, I had already discussed with our original Chairman Paul Taylor where my skills and interests lay, and as such, at the first work party in November 2002, he asked me to go through both locos to see which had the most complete electrical system, which would give him an idea which locomotive would be the most viable to begin work on. Having never been inside a 50 before, I didn't really have any idea what to expect, but I was shocked at how little remained of the electrical systems of both locomotives. After inspections by various people, the consensus was Repulse was in better overall condition, and so it was decided she was to be restored first.
The electrical cubicles of both locomotives were totally stripped, with the exception of nine of the 18 NR28 relays left in Renown, and I soon realised these had only survived because they were at the far end of the Thin Man's passage, in the most difficult compartment to get at. Both locomotives had various terminal bars missing, and there were cables hanging and lying everywhere.
Paul asked me to be his electrical officer, but I remember telling him that unless he could obtain detailed wiring manuals, there would be little chance of me being able to rewire the cubicle as I knew little about 50s at the time. He assured me he was getting copies of the manuals, so I gave him the benefit of the doubt and agreed to come to the next few work parties to start clearing the debris from in and around the cubicle.
One of the first tasks was to install fluorescent lighting in both locomotives so we could see what we were doing, and a few weeks later Paul made good on his promise and presented Mark Tinker and myself with copies of the wiring manuals, and I duly accepted the role of electrical officer. Mark Tinker was actually a qualified electrician, but decided the formal post of electrical officer wasn’t for him. One of the manuals showed the positions of the various electrical items in the cubicle, and the other gave details about what each piece of equipment was connected to, and with what cables. There then followed several weeks of poring over these manuals, and I began to have an inkling of what went where, though at that time we had no electrical equipment, so I didn't know what most of the items looked like. Mark and I began by trying to read and identify those cables that still had readable markers on them, adding our own labels written on masking tape. We were helped somewhat by many of the cables still being tied in bunches, so we were able to start placing them in approximately their correct positions.
We visited MoD Bicester to see the work Paul Spracklen was doing on 50026, and he agreed to sell us some of his spare electrical equipment. However, once I was able to examine it in more detail back at Rowsley, it quickly became apparent most of it was really only useful for spare parts. It was heavily corroded, with many missing or broken parts. We had also by then managed to obtain a quantity of NR28 control relays, so I decided to start cleaning and installing them. Shortly after this I found a supplier in Birmingham for the correct BR-spec cables. The actual manufacturer was still Brandrex, the distributor now is Anixter. Fortunately, all the cable sizes we needed are still used in the railway industry so, whilst expensive, they were readily available. To date I've installed just over 900 metres of control cabling into the electrical cubicle in 50030. A short while after this, we managed to obtain much of the electrical equipment we needed when the owner of 50023 Howe decided to sell up. This time the equipment was in much better condition, and after stripping and cleaning, was ready to be installed. I attached all the control cables from each piece of equipment as it was fitted, and laid them in to their approximate destinations, carefully marking each cable with masking tape. In this way, by the time the last piece of equipment was fitted, all it's control cables were already there. On the occasions when Mark was not there, Neil Favell gave me much appreciated help.
Cable lengths vary from less than a metre, to six or seven metres depending on how far apart the items to be connected are, and the route you have to take through the cubicle. This means that on the days I had help, we were often able to install up to 20 cables, whereas on days when I was on my own, I'd be lucky to do half that.
A further visit to where 50026 was based after it left MoD Bicester revealed their spare electrical cubicle retained all the compressor, exhauster, earthing and neutral cabling, and many of the required insulators. A deal was struck and we purchased the cubicle frame, which I stripped of all the cables and insulators and fitted them into Repulse.
Part of the haul from Howe gave us the missing cubicle terminal bars which, after cleaning, were fitted into Repulse. This allowed many of the original control cables that we had identified to be reconnected, and all of them have now been done. Refitting and reconnecting these terminal bars however in the Thin Man's passage, takes a terrible toll on the knees, with the combination of very restricted space and the chequerplate flooring.
Wiring the NR28 relays with the new cabling also presented its difficulties at the far end of the Thin Man's, as the compartment is small, dark, at shoulder height, and the relays are quite close together. In contrast, the other nine NR28s behind the cubicle switch door are much easier to get at, as the floor level is higher and there is a much wider passage to work in.
The cubicle switch door we obtained from Paul Spracklen was missing all four of the rotary switches, and only retained the ammeter, fuel priming and local start push buttons. I enquired with several 50 owning groups, but they either had no spares or were unwilling to part with any spares they had, which was quite understandable. Fortunately, one elec manual showed the manufacturers of each electrical item, and I saw the rotary switches had been made by a company called Santon, who I was already familiar with from when I worked for an industrial electrical manufacturer, as they were the Midlands distributor for Santon. And yes, it's the same company that makes electric showers!
![b2ap3_thumbnail_46.jpg](/images/easyblog_shared/AMR elec article pics/46.jpg "The cubicle switch door in 50030 after reinstatement of the rotary switches, but before the knobs have been refitted. These switches were all missing from 50030 when we acquired her in 2002, but fortunately proved to be current parts available "off the shelf".")
I contacted Santon and asked if there were modern equivalents for the four we needed, and to my surprise, when I gave them the part numbers, they told me all were still current stock items! Just goes to show that if you have a good robust design, why change it?
These four switches were not cheap by any standards, the largest one costing almost £200 itself, but we needed them so their purchase was agreed and they duly arrived. After fitting them I laid in all the cables from them, no less than 57 separate cables.
By the time it came to fit the compressor and radiator fan contactors, the larger cabling we had obtained from 50026 was already there and just needed connecting up. Obtaining the large curly ballast resistors on top of the cubicle took some time, and when we finally got them, it took both Mark and I with our heads up against the roof to fit them and connect the cables.
In front of the large field divert resistors on top of the cubicle are the 18 smaller green resistors which are mostly to operate the various cab warning lights. These lights are always on dimly, and glow bright if a fault occurs. This also ensures that if a fault light is not lit at all, the lamp has blown and needs changing. After we obtained these green resistors I then had to attach all 76 cables to them which, as with the rotary switches, took several work parties
When we went to fit the first of the three main field divert contactors, it wouldn't fit through the front of the cubicle frame however we tried to manoeuvre it. In the end I had to take off the small metal block where the air pipes are connected and re-attach it after fitting the contactor. I then had to repeat this for the other two.
Attaching the auxiliary control wiring to the front of these contactors was relatively easy. However, when it came time to install the 12 large cables on the rear of these boards, it was a different matter. We had purchased these cables from Paul Spracklen and they had lain in storage for some time. As we were fitting them in the middle of winter, not only were they stiff from the cold, they had become accustomed to their prone positions and were very difficult to get into place. In the end it took both Ian Kemp and Chris Thorn to help me get them installed, and again took multiple work parties.
Fitting the traction motor contactors was equally difficult as they are large and heavy. In one case, I had to drill out the mounting holes in the cubicle frame to a larger size, as they didn't line up with the mounting holes on the contactor itself! These six contactors have large 'Faraday-cage' type arc chutes, of which we initially had none. We did subsequently manage to obtain several, and a large box of parts from which Steve Tripp and I were able to make several more. Putting them together was somewhat difficult, as you need multiple hands, and one slip and it all falls apart and you have to start all over again. Wiring the auxiliaries on these contactors requires you to lie down in front of them as they are located very low down in the cubicle frame, almost at floor level, as trying to do it by kneeling and reaching down almost cripples you.
On the board that houses the fuses and circuit breakers, the rotary Motor Control Switch was missing. This enables pairs of traction motors to be switched out in the event of a motor failure. We obtained one as part of the haul from Howe, but some of the contacts at the rear were found to be broken, so it was wrapped up and laid aside. A couple years later during a discussion with Steve Tripp, he decided to see if there was any way the broken contacts could be repaired. As we had just been fitting motor contactors, he realised what I hadn't; that the contact blocks were the same kind as the motor contactors used. We were therefore able to take parts from a spare contact block and repair the switch, which was subsequently fitted and wired. On the fuseboard itself, all the fuses were missing, but all the MCB's were present. We have since obtained all the fuses that we need for Repulse, and have a few spares. Re-connecting the cables on the back of the fuseboard was not particularly difficult, as that is one of the few areas where there is plenty of space.
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The two large main starting contactors were obtained as part of the Howe equipment, and they were relatively easy to fit and wire. However, we have no spares or any for future use in Renown. These differ from the other contactors in the cubicle in that they have much bigger coils than any of the others and have connections for the large power cables from the batteries.
Of the boards that go in the Thin Man's passage, one is very heavy, having seven contactors on it, and it took both Mark and I to fit it. Once fitted, the contactors are very close to each other, and wiring them was very fiddly as access is very limited. The other four were relatively easy to fit and wire. The board that fits behind the fuseboard was somewhat difficult to connect up, as it's difficult to connect the cables when the board is actually bolted in place. Mark had to hold the board at an angle in front of its position, while I reached over to connect the cables, then it could be mounted on the bolts and fixed in place. On the board that houses the field divert relay, there is a long green resistor mounted above it. We didn't have one, but the 50021 Loco Association kindly gave me one of their spares. However, this turned out to be open circuit, and I was not able to source one from anywhere else. We did have various other similar resistors we had got from 37s at Booths, so my father suggested I make what is known as a 'ladder network' of smaller ones that come to the same total value. I did this and mounted it on a board in the redundant space next to the start contactors.
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A couple of years ago we were fortunate in obtaining a spare electrical cubicle from the 50021 group, which had some equipment and much of the larger exhauster and compressor cabling still in it. It has all been removed and stored for possible future use in Renown. We also obtained a genuine 50 reverser from the owner of Howe, but by that time we had temporarily fitted an ex-37 example, so I could get the six large cables from the divert contactors, three from motor contactors 1, 2 and 3, one from the field divert relay and one from one of the start contactors, into their proper positions. While the main cam mechanism is identical, the auxiliary contacts are completely different on a 37, and were incompatible. Chris Thorn offered to make a second set of auxiliary contacts, copied from the original, for future use in Renown, so we left the 37 reverser in Repulse until he had done this. As a result, the 'proper' one was only fitted into Repulse and connected up in 2014. However, these reversers are large and very heavy, and it took four of us to remove the 37 one and fit the proper one. We have two spare reversers in total, one of which now has the duplicate set of correct aux contacts Chris made.
I am at present re-installing the plastic control air pipes between various equipment in the cubicle. As soon as I started it became very clear I should have done it before much of the wiring was installed, as I'm now having to work in very restricted spaces around and in-between bunches of cables, and trying to get spanners in is extremely difficult. I have also set about identifying the remaining severed cables under the floor around the electrical cubicle and generator room of 50030. The second part of this article will describe our work in sourcing the electronic control units used in a Class 50, as well as the remaining work required to complete 50030 in electrical terms.
Renown Repulse Restoration Group is holding an Open Day on Sunday 21st June 2015 from 2 PM onwards at our Rowsley South, Peak Rail base. We hope to attract new volunteers and investment into our project. All are welcome, whether experienced preservationists or complete beginners! RRRG members will be on site to show you around 50029 and 50030, as well as discuss our facilities, restoration plans and how you can help as a future volunteer for RRRG. We look forward to seeing you then and there. Peak Rail are also hosting a classic bus event on the same day, providing an additional attraction for visitors to the railway.
The latest issue of the RRRG members' newsletter is now available to view on the website! However you have to be a current, paid up member of RRRG in order to view it. If you would like to join and catch up on all the latest news regarding the project, please read about our range of membership benefits and options. All users of our website are welcome to view the previous issue of the newsletter and all back issues.
We've also been doing a bit of website housekeeping. Once you are a registered user of the site and logged in, you will now find a special Subs Renewals menu under the User Area menu. With this you can easily join RRRG for the first time or renew your membership if it has expired. As 50030 approaches the completion of its restoration, we appreciate your membership and support of RRRG.
It has come to our attention that a popular railway enthusiast periodical has recently published a rumour that 50029 is to be sold for parts to a main line operator of the type. We wish to categorically state that this rumour is not true. Whilst most of our restoration efforts are concentrated on 50030, we are not neglecting 50029 and it is still our intention to restore both locomotives in the fullness of time. We have not been approached and we have not approached any other parties regarding the sale of either of our main assets.
Many times we are asked "When will 50030 be ready?" to which our answer is "We aim to have Repulse ready for 2017 and if enough people want the locomotive to run by that date, it will happen, but if not it will take a little bit longer." We are not short of money and we also have (or know how to obtain) practically all the parts that are required to complete both 50029 and 50030. However we would welcome additional volunteers to work on the locomotives at Peak Rail as this will undoubtedly aid us in achieving our 2017 target. We intend to hold an "open day" later in 2015 to allow interested parties to meet our team and inspect progress. We hope that this will encourage more people to volunteer with us, regardless of your skillset. Working parties are currently being held most weekends and the latest news and progress will be posted on our website. Further details of the open day will be announced nearer the time.
No, we haven't packed up and ceased to exist. Yes, we have been a bit quiet. Sorry about that - normal service to be resumed but a number of us have had things other than RRRG to deal with and our day lives have got in the way.
Ian Kemp and Dave Rolfe decided today to tackle a job we started some time ago but ended up leaving to another day. This was to remove the remaining radiator securing nuts, so that we can lift the radiators out of 50030 and have them sent away for overhaul. Given that the radiators were most likely last removed at refurbishment in the mid-1980s it goes without saying that the fastening nuts were stuck on very firmly indeed. We had previously managed to remove three of them, leaving five left to do. A potent combination of elbow grease, tools (and broken tools), purple language and in the case of one particularly stubborn nut, chiseling has now freed all eight nuts and the radiators can now be lifted out. It's the seemingly little tasks like this that end up taking so much time. Photos courtesy Ian Kemp.
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With many thanks to the Nene Valley Railway for inviting us, RRRG will be operating our sales stand at Wansford station during the the Winter Tornado gala this coming weekend (2nd and 3rd November). Any railway enthusiast must acknowledge the sheer achievement that the successful completion of 60163 Tornado represents and we are proud to help support the A1 Steam Trust as their locomotive stars in what should be a very good event.
We have recently taken delivery of a chip and PIN credit card terminal, allowing us to take credit card payments easily on the sales stand. This aplies not just to this event but to all future sales stand operations. We believe this flexibility in accepting payment, coupled with our keen prices, will make our stand even more appealing to our loyal customer base. We look forward to seeing many of you over the coming weekend.
Following on from news and developments earlier this year on the work we have commissioned to build two CU2 field divert units for use in 50029 and 50030, we can report with great pleasure that this project reached a successful conclusion today. Our contractors invited 50030 Electrical Officer Andy Rowlands to view the rebuilt units, and demonstrated as the relay in each unit was energised and gave output to the correct terminals. Each unit was tested multiple times with no problems arising. We were pleased to note that our contractors have managed to replicate the original solder tracks from the sample unit supplied as the template. Now that we have taken delivery, the units can be taken on site for trial fitting and cabling up, before being stored securely off site until such time as they are needed. Photos courtesy of Mark Brown at IES. This work has not been cheap and we would greatly appreciate the support of Class 50 enthusiasts either by joining RRRG and buying shares or supporting us via our online shop.
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We are delighted to announce that our 2014 calendar Class 50s Then and Now is available to order from our online shop. The calendar has A4 sized pages bound in the middle to allow the month layout to drop down and reveal the accompanying photograph. Each month features full page shots by noted railway photographers of a preserved Class 50 locomotive together with an inset of the same locomotive in its BR service days. The calendar is available to order from our online shop, priced at £6.95 + P&P. This production is a joint venture between RRRG and the Fifty Fund with proceeds going towards 50029 and 50030 as well as 50031, 50035, 50044 and 50049. See below for page images of each month. The calendar is printed on high quality paper equivalent to the well-known Rail Photoprints/Platform 5 calendars and is of equal quality to these well-known publications.
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We are pleased to announce that a series of new RRRG-branded mugs are now available in order to raise money for our project. Currently we have available mugs featuring side-on drawings of 50029 and 50030 individually (which we have taken care to make into what we hope are the most accurate Class 50 drawings on the market!) as well as a special design featuring both 50029 and 50030 as if posed around the turntable at Old Oak Common. This latter mug design is to celebrate the unique nature of RRRG; the only Class 50 preservation group to own two locomotives! Click on the images and captions below to be taken to the appropriate product page in our online shop. RRRG members will get a 10% discount if logged into our site as a recognised member (you may need to go through site registration to attain this status).
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| 50029 mug | 50030 mug | Two Class 50s mug |
RRRG Officer Mark Burrows recently visited our electrical contractors to view progress on a number of electrical machines we are having overhauled for use in 50029 and 50030. Here are some pictures of the work we have in progress on electrical machinery.
We have amassed a number of "duplicate" electrical machines over the years, partly with the intention of locating better condition items than are already inside 50029 and 50030 (the major electrical machines are intact in both locomotives but in poor condition after years of disuse) and so reduce the cost of overhauling them as well as the cost of extracting the machines from inside the locomotives in the first place. For example, in addition to the exhausters inside 50029 and 50030, we have two others currently with our electrical contractor. One was obtained from a scrap Class 37 at Booths and the other was purchased in almost fully overhauled condition from Unipart Rail some time ago. The latter had been in store for some considerable time and had deteriorated slightly as a result. Both of these are now finished with the ex-Booths machine having had an oil leak repaired and the ex-Unipart motor blower having received a light overhaul to bring it up to the "as new" standard we are aiming for with our restoration project.
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| Two overhauled exhausters seen in April 2013. | A traction motor blower which is at an almost complete stage of overhaul, waiting only for a new bearing before it is complete. |
Each of the electrical machines we send for overhaul and refurbishment is fitted with new brush gear as illustrated in this close-up of the fan motor in the newly-overhauled traction motor blower, and the opportunity is also taken to refurbish the "snail" casing for this machine.
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| Close up of the fully overhauled brush gear in our overhauled traction motor blower. | The "snail" fan casing from the motor blower has received an overhaul and respray too. |
A full set of pictures from the visit can be found in the RRRG image gallery.
We are pleased to announce that we are now able to offer a cou
rier delivery service for purchases from our online shop, in addition to the regular Royal Mail services. Royal Mail raised their prices and changed their services as of April 2013 and regrettably we have had to pass these alterations on to our customers. A side effect of the changes to Royal Mail's prices has been the effect on our ability to offer fully insured delivery for valuable items purchased from us, such as our range of Hornby models. Delivery by courier can be more competitively priced and just as quick as Royal Mail, with a two day service available in most cases. As a result, our range of Hornby models can now be purchased at very keen prices and with even more competitive delivery options! Why not check out our range? Remember you'll get discounts of up to 10% on the published prices if you are an RRRG member!
Mark Burrows and Dave Rolfe were on site over the weekend of 4-5 May.
Dave came to Mark's house on Sunday morning, and together they loaded five fire bottles in to Dave's car, and put three in Mark's. This took somewhat longer than expected: over an hour to load up! However this was partly because one of the bottles was full and they decided to partially blow it down to make it a bit lighter. The fire bottles are now stored on site at Rowsley. They originate from scrap 37s at Booths and are probably in better condition and easier to recertify than the ones already inside 50029 and 50030.
Wasps have attacked one of the wooden blocks under the ex-50008 power unit, which is now not too healthy. We had a choice of either getting a mother of a crane in to lift the power unit and replace the block, or do something else. After giving it some thought, Mark devised a brace that should stop the wooden block collapsing. We have bought some 10mm thick metal plates from Booths, who cut them to size for us, but they now need drilling. Mark picked them up and took the plates to Bowers last week. At Rowsley we have some inch threaded bar, with nuts and washers. Mark's idea is to use this, with some that Bowers are going to buy for us, to fasten the plates either side of the wooden block. Mark intends to take it to Bowers to show them what we are after.
Chris Thorn also asked Mark to take some air horn back plates to Bowers to get them drilled out to accommodate class 37 style air horns, so he picked them up this morning, and will take to Bowers with the threaded bar.
Whilst on site at the weekend, Mark also removed five sections of conduit from 50029 (basically to allow access to a piece that were wanted for 50030. He has removed the section that we actually want to use in 50030 and has cleaned it up and fitted it in 50030. The damaged section from
50030 that this section is to replace, has also been cleaned, as Mark intends doing a "cut and shut" on it, to use it in 50029.
Dave has been internally cleaning oil and water pipes off the ex-50008 power unit; the oil pipes are full of sludge and the water pipes have a
significant amount of loose rust in them. He has also been painting some of the large mounting brackets off the power unit.
Renown Repulse Restoration Group has placed an order with a noted locomotive electronics expert for testing of a CU1 main control units and the rebuild of KV10 load regulators using modern components. The CU1 acts as the "central brain" of a Class 50, receiving and sending signals from and to all the other electronic control units in the locomotive. There are two KV10 load regulators in a Class 50, one is denoted CU3 and controls the main generator output. The other is denoted CU6 and controls the ETH generator. A KV10 is transformed into a CU3 or a CU6 by means of pairing with a control card CU3A or CU6A.
As with many electronic components of the Class 50, the KV10 design is full of obsolete components and with an eye to the future we feel this work is essential to our goal of "future proofing" 50029 and 50030 and ensuring them a long and secure future in preservation. The original design suffers from a tendency to "lock on", whereby faulty circuitry causes the CU3 to lock in the full position even if the power controller is at its minimum position. The only real solution is to repair the faulty circuitry but that repair knowledge gets ever more scarce with the passing of time. As a result, we feel that the decision to purchase four rebuilt units (one main and one ETH generator control unit for each of 50029 and 50030) is money well spent.
There are actually two sub-types of KV10, denoted B1 and B2 with slight differences in component types. RRRG has over twice as many B1s as we do B2s but our stock of CU3A and CU6A cards are only confirmed to work with B2 type KV10s. The rebuild process uses only the case, heat sink and thyristor from the original KV10 and as a result the control cards become obsolete as the components they contain are now integrated into the main unit. We intend to supply type B1 KV10s for the rebuild project with a decision on disposal of the type B2 units and control cards to be taken at a later date.
The following two shots show a rebuilt CU6-type KV10 installed in 50008 Thunderer. The first shot is taken from the Thin Man's side and the second is opposite the exhauster. Click on either to enlarge (opens in new window).
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Needless to say, this work will not be cheap and we really need the support of the preservation community. Perhaps you could donate to our project, or become a member of RRRG and buy shares, or browse our online shop for items of interest? Your support is what has got us this far already and it is much appreciated.
On 23rd and 24th February the RRRG sales stand attended the Nene Valley winter steam gala. The stand was predominantly coordinated and managed by Tim and myself; Mark was around on Saturday morning to bring stock down and help set up but couldn't stay because of a family appointment. It was cold. Very cold. So cold, in fact, that it was the first time in ten years of RRRG trading that we have had the sales stand out whilst snow has been falling... That said, it was nice to see a preserved line trying something new and trying to extend their operating season to make more money. Saturday trading was reasonable although in the afternoon the star attraction no 70000 Britannia unfortunately derailed at Yarwell Junction whilst backing onto coaching stock at the end of a run round manoeuvre. The non-availability of this locomotive undoubtedly affected attendance levels at the gala, which was a shame. We sold a mixture of items but no really high value items such as the boxed Hornby model sets you see in our online shop, sold, which was again a bit of a shame.
The final figures for sales were:
Saturday 23rd Feb: Total Turnover £161.55
Sunday 24th Feb: Total Turnover £137.25
Total RRRG profit after fees was £93.08 for the weekend, which was a respectable showing. Renown Repulse Universal, RRRG's commercial wing, also sold a number of items from the stand over the weekend to create profit which can be re-invested in RRRG and its activities (such as the hosting fees for this site!) and contributed to the putch fee.
Even though I fell ill late on Sunday evening with one of the worst colds I've had in many a year, doubtless aided by standing out on a freezing cold platform all weekend, it was still a worthwhile event and our thanks go to the Nene Valley Railway for inviting us to have a stand once again.
As long-term followers of RRRG will know, for some time now we have been investigating the remanufacture of CU2 field divert units to replace the ones missing from our locomotives. Our contractors for the job, Industrial Electronic Services Ltd, had analysed a genuine CU2 kindly loaned to us by another Class 50 owner and were confident they could reproduce the circuitry and components in the unit, using modern equivalents where possible/necessary. They had however hit quite a snag when it came to replacing the little relay in the original unit. The CU2 is a really amazingly compact piece of equipment for mid-1960s electronics as seen in the photo of the loaned unit below. The relay in question is the small black box seen in the centre of the picture. It switches at the operating voltage of Class 50 auxiliaries, namely 110v DC which brings about the problem of how to find a modern equivalent. Electronics is obviously one area where technology has progressed leaps and bounds in the near-half century since the Class 50 was constructed by English Electric and relays to operate at such high DC voltage, let alone such compact ones (it appears the original was custom-made for EE by ITT) are almost completely obsolete these days. Most modern relays, even of a size too big to fit the case, would burn out very quickly if asked to switch 110v DC.
We thought about various ways to overcome the problem. Inverting the current to AC, using an AC relay and then rectifying it back to DC was suggested but dismissed as impractical. 50030 Electrical Officer Andy Rowlands suggested using a spare NR28 relay, as used elsewhere in the locomotive to switch 110v DC. It wouldn't fit in the box for the CU2 (and the CU2 is deliberately designed to be compact as it fits into a very tight space in the cubicle) but Andy reasoned it could be mounted externally and wired in. We supplied IES with a couple of NR28s to test the theory and they agreed it would work but felt the new divert unit would need some circuit modification if it were to be used. IES decided to have another look at the relay market and managed to source a relay from the US which has a 24v coil and can switch up to 220v DC. IES ordered a number of these relays on our behalf and have now advised us that they have arrived and appear to work fine in our 110v DC application.
We now expect progress to be rapid on the rebuild of these electronic units. IES have invited Andy to inspect the new relays in person the first week in March and if approved by us, IES expect to finalise the design within the next couple of weeks with production of the two units requested following imminently thereafter.
A full description of the electronic units in a Class 50, and how many of each type RRRG has, can be found in RRRG newsletter Issue 23 (Autumn 2011). Since that article was written, we have acquired one original CU2 from another Class 50 owning group however we still intend to have two units built by IES to cover for possible future failures.
RRRG will be attending the Nene Valley Railway steam gala with our sales stand at Wansford station on February 23-24. We will have our usual selection of books, DVDs and keenly-priced Hornby models on sale and we thank the NVR for extending us the invitation to attend their events once again this year. Come along and say hello, there's a good lineup of steam power on show including 70000 Britannia, and you can chat to RRRG representatives about the state of the project and how you can help.
A few bits of news to report.