Restoration diary

One of the electronic control units in a Class 50 locomotive is the CU5 radiator fan control unit.  It works together with the CU4 coolant flow control unit under the control of the CU1 main control unit to maintain the correct cooling water temperature by adjusting the speed of the radiator fan.  Both RRRG's locomotives are missing this unit.  The original was designed by Hawker-Siddeley for English Electric and utilises components that, by the standards of the 21st century, are thoroughly obsolete.

A good friend of RRRG, based at the Gloucestershire and Warwickshire Railway, offered his services to construct a compatible replacement unit using modern electronics - needless to say, we were and are extremely grateful for this offer!  Shown here is the item which is now nearly complete.  The main circuit board has been deliberately left unattached to the case at this stage, as the next step is to test the unit by connecting to a suitable 110 volts DC source in order to ensure it performs correctly.

An original unit was borrowed from the 50021 Loco Association, and this new unit has been produced to resemble it physically, while using greatly-simplified circuits (as the original was over-complex for what it needed to do), modern components and utilising a small programmable microprocessor to replicate many of the functions of the original.  We will provide more updates on this sub-project when they become available.

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.

We are pleased to announce that the first of our rebuilt KV10 electronic units has been completed.  As we reported in April, we placed an order for four rebuilt KV10 units, two per locomotive using modern electronic components as opposed to the obsolete 1960s versions of the original.  This picture shows a rebuilt CU6 ETH KV10; we have ordered two of these plus two rebuilt CU3 main generator units (the originals are identical to each other and are transformed into CU3 main generator or CU6 ETH generator KV10s by addition of a CU3A or CU6A daughter card but the rebuilt versions incorporate the electronics of the daughter cards into the main unit and so differ from each other).  The two photos above show both sides of the rebuilt unit's circuitry.  By way of a comparison, below is a view of the original 1960s vintage circuitry in the KV10.

The completion of the first rebuilt KV10 marks a further important stage in the restoration of 50029 Renown and 50030 Repulse.  The cost is just over £1000 per unit and we need the help of the enthusiast community to help us fund future stages in the restoration project.  Can you buy something from our online shop or consider joining RRRG and buying shares to become part of this exciting locomotive rebuild project?  We are keenly aware of the anticipation in the enthusiast community for 50029 and 50030 to haul trains once again but we are going to need your help to achieve this.

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.

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.

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.

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).

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.