Restoration diary

On July 12th, Mark Burrows went through our stores area sorting out the doors for the electrical cubicles of both locomotives, to see if any were missing, and if so, which ones. We seem to be missing just one small door for Renown. Ian Kemp, Pete Carter and Dave Rolfe refitted the heat exchanger onto the ex-50008 power unit, including the replacement end piece recovered from the power unit in Repulse. Dom Jackson assisted Andy Rowlands belling out cables inside the electrical cubicle of 50030, as part of the completion of the electrical system and in continued preparation for the first fire-up of the locomotive.  At the end of the day, Dave, Ian and Pete covered the PU with a new large tarpaulin as the old ones had started to deteriorate.

The work party on 19th July was attended by myself, Dave Rolfe, Peter Carter, Ian Kemp and Mark Burrows.  Mark spent most of the day making a start on clearing one of our sotrage areas, as its current location is required by Peak Rail to extend their engine shed.

At the last work party the heat exchanger was repaired, cleaned, painted and refitted to the ex-50008 power unit.  This allowed Dave, Pete, Ian and myself to refit the pipe work around it.  The main aim of the pipe fitting is to complete the oil lubrication system so we can hand prime the oil around the engine which will lower the risk of damage to the bearings when the engine is barred over. By the end of the day all of the main oil pipes had been fitted, except one which cannot be fitted as the sleepers that the power unit is sat on are in the way. We now need to order new oil filters before the filter housings can be fitted.  The main image for this entry shows the refitted heat exchanger together with the pipework we managed to reinstall during the work party.

I spent the afternoon assessing the cabs on Repulse with a view of restarting the repair work on them, then I made a start on checking what cab parts we have in store and what reusable parts are in the e- 50037 cab.

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!

Ian Kemp, Peter Carter and Dave Rolfe carried on fitting oil, water and fuel pipework to the ex-50008 power unit, but on the side facing Renown, so no photo opportunities were possible today.

In preparation for the open day on June 21st, I washed down the outside of the electrical cubicle frame in 50030 and undercoated it, as it had become dirty from repeated handling since it was originally painted about five or six years ago. I also cleaned and undercoated the two cubicle doors from the fuse and MCB compartment. I brought three more cubicle doors home to clean.

Just a reminder that we are having our Open Day on the afternoon of Sunday June 21st where RRRG members will be on hand to give guided tours of the project and discuss progress. We hope to see you there!

Ian Kemp, Peter Carter and Wes Needle continued fitting coolant and oil pipework to the power unit, while Dave Rolfe carried on painting the other side of the power unit.

I removed the battery charge contactor so I could clean and undercoat the compartment where the CU2 and CU7 go, then did the same for the compartment underneath where the CU1 sits, in readiness for having them temporarily fitted for the open day. Topcoat will be applied next workparty. I also cleaned the dirtiest two of the cubicle doors ready for painting.

Electronic Control Units

One of the major talking points when RRRG first acquired 50029 and 50030 was the availability, or otherwise, of the various electrical control units. The Class 50 has a reputation for being electrically complex – some would say needlessly so.  Pre-refurbishment they were even worse as EE (with assistance from BR) had tried to produce a jack-of-all-trades locomotive.  Many of the features were either rarely used or prone to faults, and most were removed by BR during refurbishment.  The electronic control units are mostly unique to the 50 although some are common to other late-build English Electric locomotives.  Unsurprisingly, all the control units had been removed from 29 and 30 before we bought them and so we had to obtain replacements.  We also felt that it would be worth trying to update the electronics to modern specifications where possible, because the 1960s designs either use completely obsolete components for which no modern equivalents exist, or incorporate design faults, or both.

This is a list of the various control units in a Class 50 and how we have obtained them or can obtain them if we still need them.

CU1 – The main control unit CU1 is the central “brains” and obtains information from a number of different sources, namely from the cab controls, engine load condition (from the load limiting potentiometer) and from the traction currents.  This information is passed to the CU3 and in turn the engine governor.  We have one complete, tested unit, one complete and untested unit and the parts to make up another.

CU2 – the field divert unit, the electrical equivalent of the gearbox of the locomotive.  It controls the three stages of field weakening which occur at approximately 25, 40 and 60 mph depending on trailing load and ruling gradient.  We were missing this item from both our locomotives and the former owners of 50021 kindly loaned us an example which we took to an electronics specialist company who “cloned” it and built us two copies to modern standards.  Ironically, shortly after this, we were able to purchase an original Class 50 unit, though this has yet to be tested, however the original EE unit is known to be very reliable in service.

CU3 and CU6 – also known by its EE designation KV10. The CU3 sets the field current from the main generator as a summation of all the input signals and the CU6 similarly controls the ETH generator output. The main body of the unit is identical but is turned into a CU3 or CU6 by adding a CU3A or CU6A daughter card. Originally we had no KV10s but we adopted a policy of buying them whenever they came on the market in the intervening years and we built up quite a collection. However the KV10 is a classic case of obsolete and temperamental electronics and a respected locomotive electronics expert brought a rebuilt version to market some years ago with completely modernised components. We felt that ordering two each of the rebuilt CU3 and CU6 units for 50029 and 50030 was money well spent. The owner of 50008 Thunderer has also chosen to fit these modernised KV10s and is gaining operational experience with them which will prove invaluable to RRRG.  The new design incorporates the electronics of the CU3A or CU6A into the main unit and eliminates the need for a daughter card.

CU4 – coolant control unit.  This unit is designed to monitor the temperature of the cooling water in the two coolant circuits and open/close valves to route the flow of water correctly.  It also sends signals to the CU5.  We have none but the Class 50 Alliance has developed a modernised unit which will be made available to us in due course.  It would have been possible to recreate the original CU4, which was built for EE by Hawker Siddeley, but the new design employs proven marine technology which would be acceptable to Network Rail (an important consideration for the C50A) and, together with a C50A-planned CU5 rebuild would eliminate "bugs" in the system which can cause the engine to be over-cooled in some circumstances.

CU5 – radiator fan control unit, it receives the signals from the temperature probes via the CU4 and controls the speed of the radiator fan accordingly.  We had none but again we were able to borrow one from another Class 50 owner.  Adrian Spencer of Cotswold Mainline Diesel Group, another noted locomotive electronics expert, was again able to copy this circuit and build a copy using modern electronic components.  We have also taken the opportunity to have a batch of the temperature probes remanufactured, in partnership with other Class 50 owners.

CU6 – Regulates the output of the ETH generator. This is basically the same as the CU3, but adjusts the ETH generator field strength to suit varying load demands according the number of coaches requiring electrical heating.

CU7 – ETH field detector unit.  Basically it sees if there is a feed from the coaches which allows the ETH generator to electrically heat them.  It also detects if an ETH fault occurs in a coach, and if one does, in conjunction with Heating Over Volts Relay, it switches off the ETH feed to the coaches and returns the power unit to idling.  It also detects voltage from two 50s in multiple and prevents “doubling” of the ETH supply if this is the case.  This is a fairly simple circuit which I was able to rebuild and install in 50030.  I also obtained the parts to build one for 50029 in due course.  It was a CU7/HOVR fault which caused 50050 Fearless to shut down during the "Fifty Terminator" railtour of March 1994 as for some reason the engine was shut down instead of being returned to idle.

The CU8 designation was never used, for reasons lost in the mists of time, so isn't relevant to our restoration project.

The CU9 is the automatic voltage regulator, or AVR, and basically maintains the output from the auxiliary generator at 110v DC so the compressors, exhausters and motor blowers do not overspeed.  There are two types: electronic (CU9A) and carbon pile (CU9B), both types are compatible and there is one per locomotive.  The majority of Class 50s were fitted with the original ‘Carbon Pile’ unit, and ten 50s were fitted with an electronic version, but because the electronic types additionally controlled battery charging and also contained gas-sensing equipment, their complexity apparently made them unreliable and were replaced with carbon pile units, which are slower reacting but more reliable.  We have an overhauled CU9B for use in 50030 plus two untested CU9Bs.  We may decide to commission new build versions as this unit can also be improved upon with modern electronics, effectively producing an updated CU9A.  We are currently unaware of anyone who could test our CU9Bs and this is also something we need to consider.

The CU10 is the speed control unit.  It's also known as the ‘AEI’ unit after its manufacturer, the Birmingham company Associated Electrical Industries.  It is a complex device that receives signals from the axle driven transmitter unit, and sends signals to the cab speedometers.  It can be adjusted to take into account wheel-wear.  Six card slots but not all these are used on a 50.  One CU10 per locomotive.  We have two units plus some of the control cards, but as the Class 50 Alliance have designed a modern version, we will probably obtain one in due course.

CU11 was the slow speed control unit which was removed at refurbishment.

The CU12 is the lighting delay timer.  It turns off unnecessary lighting 15 minutes after engine shutdown, such as internal lighting and marker lights, should they be left on and the main battery isolation switch be left in the ‘ON’ position. One per locomotive.  It's questionable whether this unit is really necessary for preserved line use, as it was really designed for times when a 50 might finish its BR duties and then be disposed of on depot by a driver with other things on his mind, so that he might forget to turn the lights off and the batteries would be drained and the locomotive subsequently failed the next morning.  This unit is actually still present in 50029 so we could use this as a template to make one for 50030, if we feel we need to.

Things Still To Do

We still have to tackle the difficult, and probably expensive, issue of the severed traction and ETH cabling under the cubicle.  I have been advised not to through-crimp traction cabling, so it will need replacing with new cable at some point.  We may have to use the services of a specialist contractor for their replacement.

The brake frame needs rewiring once the exhauster underneath it has been changed for an overhauled one.  The Driver’s Safety Device (DSD) relay box needs new cabling laying in as the original cables have long gone, likewise for the DSD speed switch in the cupboard underneath the hotplate in No.2 cab.  The comprises several pieces of equipment, including relays plus hand and foot operated switches, which automatically shuts off power and initiates a full brake application after 5-7 seconds if the driver becomes incapacitated and removes his foot from the pedal in the cab.

All the cab desks need the cable crimps cleaning, the lampholders behind where the instrument panels go will need either cleaning or replacing, we still have to source or make the switch panels that go in the ceiling above the driver, and the master controllers need freeing off much more than they are now.  The traction motors will need removing for overhaul, and the traction cable connection boxes under the locomotive will need refurbishing.  The overhauled exhausters and compressors will need reconnecting once fitted.

The engine governor and the load limiting potentiometer, or vane motor, need overhauling.  The electrical rebuild of 50030 has been challenging yet very satisfying.  Anyone fancy helping with 50029?

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!

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.

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.

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.

Mark Burrows and myself were on site today.  A slight mix-up over keys to the container resulted in a delay getting started and curtailed the working day somewhat.  Mark scraped off the worst of the crap from both the 037 cab and no. 2 cab of 30, then painted grey undercoat on the cab front of 037 to 'smarten it up a bit'.  The paintwork on all of our assets is looking faded and dirty after several years of no attention.  I pulled out the cables from under the floor in front of the aux gen that go to the load limiting potentiometer to bell them out. I identified and marked all but one, which will require further investigation. I did the same for several smaller severed cables from the cubicle to the main gen. This took all day as I was doing it on my own, so I had to make repeated trips into the Thin Man's passage to move the belling lead.  Although the work I've described here doesn't sound like much, it did take up a whole day but was very satisfying as it pinned down more of the cabling inside 50030.

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.