1. Locomotive and Coach Axle Driven Alternators (ADAs) - Following the discovery last year that one of the coach ADA internal pulleys had shed one of its flanges, we procured new stainless-steel pulleys with stainless flanges. Alan Parkin arranged for Daniela Works to machine the pulleys and have the flanges TIG welded on, so they cannot come off in future. Alan visited the coach on 17th February and he and Ian Greenan fitted the new pulleys and replacement belt. The ADA with the new pulleys on was tested for the first time on the loco and coach move to Carnforth on 7th March and worked well. It has continued to operate correctly on all the runs since then.
The replacement ADA pulleys were the last outstanding action on certification documentation for Ricardo. The locomotive ADA broke a belt last year, which has also now been replaced. As recommended by Keith Nicholson, a choke has now been fitted to the tender air braking system, which should greatly reduce the chance of the rear tender wheelset picking up in future (the most likely cause of the belt breakage). A final Inspection Report was prepared, along with a set of notes describing rectification actions on both the ADAs and an update to our specification document. All the documentation was then sent off to Ricardo. On 20th February we were pleased to receive an email from Alistair Leach confirming that he was happy with all the electrical overhaul and ETCS-ready documentation. These final reports brought the total number of electrical system documents provided to Ricardo for scrutiny to 256.
On 26th February the locomotive was running on the NVR so the opportunity was taken to test the tender ADA in operation with its replacement belt. It worked correctly, cutting-in as designed at around 22.5mph and out again at 22mph. The ETCS batteries were almost fully charged, so the current demand was only about 6A. At this current, the turbogen took all the load when it was connected, confirming as expected that it has a very slightly higher voltage at the batteries than the ADA and GWH chargers.
2. Turbogen Speed Displays - With the locomotive in steam on 25th February, the opportunity was taken to test the new turbogen speedometer displays, located inside the Turbogen Switch Box. Both displays worked correctly, showing the speed of our old turbogen to be 3540-3560rpm and the new Meiningen one to be 3660-3750rpm. Meiningen sets the turbogens to 3750rpm on test following manufacture. The new displays will allow us to keep an eye on governor operation on both turbogens and provide early warning of the need for adjustment as the carbon disk thrust plate inside each governor wears.
3. Cambrian Testing Preparations - In preparation for Cambrian testing, the two spare headlamps (which are required for tender-first running) were taken out of store on the coach and tested. One had a split covering to its flexible conduit, so this was replaced, and both headlamps were tested in-situ on the tender.
Preparations were made for measurement and logging of ETCS supply voltage and current during the Cambrian testing. One of the ETCS supply wires was brought out through the side plate to the ETCS I/O Panel. This allowed connection of a Bluetooth-enabled clamp ammeter. A second meter was attached to the spare ETCS supply output to measure the delivered voltage. The measurements we take will enable us to calculate the power consumed under a full range of real operating conditions. We can then confirm the headroom that our power supply provides, and the endurance of the system when operating on batteries alone.
A final visit to Wansford on 5th March included a check that both the meters fit, whilst allowing the front cover of the ETCS I/O Panel to be closed over them for protection. Each of the two meters will record up to 10,000 readings. We shall set them to take readings every two seconds. This gives us 5.5 hours of recording – sufficient for a full night of testing between Coleham (Shrewsbury) and Newtown. The data can then be downloaded via Bluetooth to a phone. We will analyse the data between night sessions and may change the monitoring interval if needed to allow more detailed investigation of peak currents.
4. Coach Electrical Work - Electrical work on the coach during the period included completion of the No. 7 exam electrical jobs, working alongside Alex Williams. All electrical tests and inspections were passed.
Although they are all still working well, the smoke and heat alarms in the coach are now over their nominal lifetime of 10 years, having been installed in 2024. A phased programme of replacement has been agreed. It was decided to upgrade the current single carbon monoxide alarm to two alarms, positioned in the corridor so they provide good protection for any CO leaks from the two gas-burning appliances – in the kitchen and boiler cupboard. These alarms come with sealed 10-year batteries, so we will not need to worry about them until 2035. They also have a display to show percentage CO detected (and incidentally, ambient temperature).
We also took the opportunity to review the type of alarm in the boiler cupboard and Electrical Control Cabinet. These were originally fitted as multi-sensor alarms, featuring both heat and smoke detectors. However, since it entered service, the coach has suffered from false alarms when the engine and coach are travelling together tender-first and the drain cocks are open. We have not been able to conclusively prove which alarm is triggering, but crews have made sure that compartment windows are closed, and the problem still occurs. We believe that it may be caused by water vapour entering one of the floor vents, which are a feature of both cupboards. In consultation with Aico, the alarm system manufacturer, we have therefore decided to change the two cupboard alarms to heat-only sensors, as typically used in kitchens where steam may be present. These sensors are set to 58 deg. C, so they will provide very good protection against overheating or emerging fire in either cupboard, whilst being immune to triggering by steam or water vapour. If successful, this should prevent the system making the electrical team unpopular by waking all the support crew up when they are trying to get some more sleep during early-morning positioning moves. The remaining alarms are all working fine but will be replaced as a precaution later in the year.
The Cambrian testing (more details below) involved running tender first on all the return journeys. This included regular periods with the drain cocks open, and we were pleased to note that no false alarms occurred in the coach, so we think there is a good chance that we have correctly identified and solved this one.
5. ADAs In-service Experience Trial Preparations - The last electrical job to complete before going main line was provision of paperwork to support the ADA In-service Experience Trial. This important process is part of the scrutiny by Ricardo of our two new ADAs. The trial lasts for 2,000 miles, during which time the ADAs are operating under temporary Attestation Statements. To prove that they are fit for continued service we need to collect measurements of the performance of each ADA whilst in use. We have prepared forms for crews to use. Together with regular special inspections, the forms will provide evidence for Ricardo’s final scrutiny on completion of the trial. If they are satisfied with the evidence, we provide they will issue full Attestation Statements. These will allow both ADAs, and any more we make to these designs, to operate permanently on the main line on both locomotives and coaches.