At the back of the engine is the turbo, and having no knowledge of anything having transpired with it other than Gwili having changed a hose which feeds oil to it, we had not previously performed much more than a cursory exam. Today however, we spotted that the back of the turbo was covered in oil, and Andrew squeezed in and found that the hose Gwili had fitted was loose.
Just before the loco left for South Wales, one of our last major tasks had been to re-arrange the air intake. As the loco came to us, it still had the small "genset" type air cleaner from its days underneath the Glasgow Post Office, and this drew air from within the engine bay, which is bad practice. We had sorted out a suitable air cleaner element, designed and manufactured an enclosure, and arranged ducting down to the turbo. To complete the join, we had had the turbo inlet off and welded on a suitable length of pipe as a cuff for the rubber elbow to clamp to. OK, the turbo inlet should have had 4 bolts holding it, and we let it go with three, but we knew it was sound and that the turbo impeller was in A1 condition.
But Andrew suddenly spotted that the turbo inlet was now held on with two plated bolts. Withdrawing these revealed that they were metric coarse threaded, whereas the turbo tappings, in line with practice of the period, were fine threaded imperial. We were not ready though for the state of the impeller behind. Something has apparently gone through the turbo while the loco has been down at Bronwydd Arms, and what with bent and chipped blades, plus an uncomfortable amount of play in the shaft, we immediately cancelled the test run. The turbo must come off before any other damage occurs. I will leave you to surmise quite how we felt about this latest revelation as to "things that have mysteriously happened while it has been away". It gave me a migraine.
On Wednesday I answered the phone as I was trying to catch up on some admin. "Are you bored?" asked Andrew. I decided it was rhetorical. "Cheedale is out on thunderbird duty" he continued.
Now that was really too good to miss. It seemed that D8 "Penyghent" had gone to Matlock top'n'tailing with "Lord Phil" but at Matlock declined to take power. The Austerity was pushing it all back and Cheedale would take over. This was not however entirely a celebration for Briddon motive power. Cheedale had never, thus far, ventured more than a train's length outside Rowsley whereas it must be towed down to Matlock and pull 7 carriages back up. It is not in-capable - on the contrary, on level track it has sufficient tractive effort to start a train of maybe 1800tons, whereas 7 plus an 0-6-0ST is barely 300. But in the quarry no-one tries to handle the train at 15 mph, and Cheedale probably spent most of its working life at little over walking pace. After Cheedale had shunted the errant D8 clear, I advised Rob to keep the clutch "out" on the way down and run the engine at around 1100-1200rpm so that the converter would be kept cool. I had no concerns about it coming back up the line provided it wasn't too important to keep to time.
Leaving Rob to it, but worrying like a father at an offspring's first sports day, I drove down to Riverside and photographed the train going by and again as Cheedale set off back north. For some reason Rob was running with the headlamp on as well as marker lights - maybe trying to imitate the BMACs on '901? I drove on up to Darley Dale.
As Cheedale came into sight, my heart sank - the headlamp was off. Knowing that Thomas Hill's wiring practice was to isolate the headlamp feed if the engine stops, it probably meant that the power unit had shut down. Sure enough the train rolled to a stand with Cheedale quiet. I leapt aboard, and heard briefly that it had shutdown near Redhouse with the converter temperature at 99 degrees. I got the engine restarted - and restarted - and restarted (it wouldn't latch in until the temperature switch reset) and hopped off as the Guard gave the right away, leaving Lord Phil to push it back. Later that day Rob explained that as it was so slow climbing Redhouse he'd signalled to Lord Phil to give a push. Torque converters are moderately efficient driving "forwards" but they are decidedly inefficient being driven from the back - the converter heat rejection had climbed dramatically when pushed and the temperature switch, which ought to have tripped about 125 degrees but presumably is a little out of sorts, did the rest. The decision was taken to push D8 to and fro for the rest of the day.
On Thursday I had a "do" to attend at what used to be called The Army & Navy Club in Pall Mall, so the phone was on silent and I almost missed a flurry of calls. D8 continued to be poorly, the 31 is out for attention and 14 901 - which should have been available from the day it returned from South Wales, was still pending. For the weekend the service switched to Riverside, which does not require top'n'tail operation. (Incidentally for my trip to the 'smoke I enjoyed the full range of East Midland Trains offerings - an overcrowded 153 from Matlock to Derby, a Meridian thence to St Pancras, an HST back and then an almost-empty two-car 153 combo which only went from Derby to Ambergate where a rail replacement bus was hiding at the bottom of the hill for the last leg back to Matlock.)
So on Saturday, we headed over to Scunthorpe to continue work on Beverley. With a stock of new fittings and plastic pipe, we completed the control installation for the vac system, fitted the casing doors over the exhauster, made up the joint for the filler assembly, and drilled and tapped the buffer beam M12 for "traditional" pipe clamps. A little behind-the scenes negotiation was also taking place with a view to "Tom" going there in a few weeks time, and finally we loaded our steam cleaner - which has been living at Scunthorpe for about 3 years or so - for the journey back to Derbyshire. As things stand, if we take some oil and a set of batteries next weekend, we should be in a position to run the loco up and test the installation.
Today we headed in to Rowsley early as the bus gathering was on and the place would be heaving. With impeccable timing, we arrived just ahead of Roger Wornham and his wife Yvonne. Roger was the former owner of "Tom" and had dropped by to see it operating, though we did not really get the opportunity to move it. Once they had departed, we made a start on 14 901's turbo. It took a couple of hours to get it freed off and out of the loco - not only it is a heavy lump, but the two temperature probes (typical genset features but u/s and scarcely relevant on a loco) helped make it all an awkward shape to wangle out. We extracted the probes once on the ground, and later in the afternoon removed the outlet elbow, and, to our relief, found the exhaust turbine appears undamaged, although the impeller and shaft are scrap. It will be headed to a repairers later this week. I also removed the fuel header tank for rewelding.
Meanwhile Penyghent's support crew had found first that a stop relay had jammed in, preventing the engine from starting, and that a pressure switch had gone awol, thus preventing it taking power once it had. It came off shed during the afternoon and took up its duties, thus removing the prospect of Cheedale having to reprise its role on Tuesday. Just in case though, we extracted the old temperature probe and substituted an electric one and I wired it in, so both gauges should now work in the desk. Then we moved over to James and changed the fuel filters. They were clogged and filthy, yet when we tested it afterwards, the performance is unchanged - we still can't get over 1100rpm on load. Some more head-scratching is in order.