All the locomotive and coach electrical systems are now operational.  Priority work during the period has included closing out ETCS project actions and completing electrical certification documentation.  Two new circuits have been added to the locomotive – an increased capacity power supply battery for the tracker and a pair of speedometers for the turbogens.  Work is also underway to prepare the two ADAs for their In-service Experience Trial when the locomotive returns to the main line. 

At the beginning of the period, around ten issues remained on Network Rail’s list list to be actioned by combinations of A1SLT, AtkinsRéalis and Hitachi.  We have worked though our actions and all those required for the locomotive to operate on the main line under TPWS/AWS are now complete.  Our actions have included the fitting of warning notices for the Balise antennas and Doppler Radar.  These are mandated due to the high level of RF radiation from these devices when in use.  Personnel must not come within one metre of any of these antennas without the ETCS being isolated.  Labels were also produced and attached to the brake system isolation cocks.

At AtkinsRéalis’ request we swapped the backward TPWS direction LED for a less bright one and fitted current-limiting resistors to both forward and backward LEDs.  We also removed, cleaned and repainted the AWS sunflower bezel in satin black and refitted it with black screws. These were all requirements of the Human Factors assessment of the installed systems back in August.

The last action on us was to finalise the locking arrangement of the tender ETCS Driver Machine Interface (DMI) into its enclosure in the top of the brake box.  When this was originally trial fitted back at LMS it was found that a combination of tolerances meant that the cam locking tabs would not correctly engage to secure the DMI in position.  We have now made adjustments to the locking tabs so that they correctly engage and hold the DMI firmly with no movement.

Once the main line ETCS testing is complete, the ETCS equipment will be placed into a special state called Dormant Mode.  In this state the ETCS is electrically and pneumatically isolated from the rest of the locomotive safety and braking systems.  It will remain in this mode until further testing is carried out, or the system is commissioned for full operation.  At the end of November we formally enacted our Dormant Mode Procedure and placed the electrical and safety systems into Dormant Mode, completing the required documentation to confirm this.  In response to crew feedback, the ETCS I/O Panel lighting strip has been fitted with a dimmer circuit to allow the light levels to be varied over a wide range.  It is possible that this luminaire will prove useful in general operations, as it provides light over the tender shelf, which is otherwise a very dark space.

The new tender Axle Driven Alternator (ADA) had already been tested during running on the Great Central Railway in August.  However, during use on the Nene Valley Railway in October it was noted that it had stopped generating.  Investigation by Alan Parkin revealed that one of the internal toothed belts had broken.  We believe this was as a result of the rear wheelset locking up, probably when operating light engine with the straight air brake.  We know that the rear tender axle was doing most of the braking whilst the new brake blocks wear in, so this can occur. 

Conversations with the belt supplier have led us to conclude that we should not change to a stronger belt.  In fact, the limited strength of these belts acts as a useful safe failure mode to prevent greater damage occurring to other components of the ADA drive train under these conditions.  The bedding-in of the brake blocks, together with an (already planned) modification to the tender brake application rate, should reduce the chance of this occurring again.  If it does, spare belts will be carried in the support coach and replacement takes less than an hour.  Following this breakage the spare belt was fitted and a replacement spare was ordered, which has now arrived.

With all the new and rebuilt systems now operating correctly we have been able to carry out a couple of enhancements which will help operations going forward.  The first of these was to fit a higher-capacity rechargeable battery to the GPS tracker power supply.  This will allow the tracker to remain operational for longer periods when the loco is out of use.  In the past, we have sometimes found that the internal tracker battery becomes exhausted whilst the locomotive is halfway up its namesake motorway on its way across the country.  The additional battery should reduce the chance of this happening.  We won’t know exactly how long it will now last until we have fully cycled both batteries with the power supply operational.  However, at the time of writing this article it is currently sitting at 24% charged, and it would certainly have run down by now without the new battery.

We have also taken the opportunity to add speedometer displays for each of the turbogens to the Turbogen Switch Box.  These are based on commercially available frequency counter kits.  Two of these have been modified to interface to the tacho output of our turbogens.  This has involved signal level adjustment and rewiring the displays to divide the frequency being displayed by 10.  This conveniently displays a typical 336Hz tacho output as 3360rpm.  A power supply has been added and the pair of circuits has been mounted in a small case on the front panel of the Turbogen Switch Box, ready for testing when the locomotive is next in steam.  The speed displays will allow us to keep an eye on wear in the turbogen governors and give us early warning that adjustment is required.

A routine inspection of the Mk1 coach ADA in October revealed that one of the internal toothed pulleys had shed one of the rings which retains the belt centrally on the pulley.  As a result, the belt had slipped out of position, although it would still work in this state.  The decision was made to move the Mk1 design to be the same as the Mk 2 (on the tender) by replacing the composite aluminium/stainless steel pulley with an all-stainless version, on which we can weld the retaining rings on.  The new pulleys have arrived and are now with Daniela Works for machining and to have the rings welded on.  They will be fitted once this work is done.

One of the BMAC marker/tail lamps on the coach ends has suffered from water ingress was replaced with a new unit in November.  The old unit was dismantled and the source of the leak was identified as poor sealing between the aluminium lamp casing and the front lens assembly.  All the original sealant was removed, the lamp was thoroughly dried out and the assembly was re-sealed using long-life flexible adhesive.  Following testing this is now in stock as a spare.

All the electrical overhaul and ETCS-ready documentation has been updated to as-built status.  The majority of this was delivered to Ricardo by mid-2024.  The only additional updates still required are to the ADA documents as a result of the changes to the Mk1 toothed pulleys.  This will be completed once the new pulleys are fitted and inspected.  The updated documents will then be delivered to Ricardo along with a final Inspection Report.  Once the locomotive is back in steam, all the electrical systems will be tested once again, and the new turbogen speedometer displays will also be tested.  The electrical team will support the main line test runs, re-entry into service and the ETCS testing as required.