Weekend Rails

what we do for our kids

Of suspension and regulation

1st September 2013

OK, hands up all of you who logged on last Sunday night or Monday expecting to find the latest post? Didn't I say assume Monday on a Bank Holiday weekend?

So while you were busy reading Monday's edition on Tuesday, Andrew and I were back at Rowsley, him to carry on painting “Libby” and me to continue work on “Ashdown”. Actually first I was trying to get my hands on a 20mm conduit inspection tee, but as I was not in the mood to dash over to my regular suppliers in Sheffield, and have yet to learn where to get everything in Derbyshire, drew a blank and left the conduit disconnected in order to get the wiring in place. By the end of the day it was all ready, save that the LED we had fitted in to the cab bulkhead the previous day wouldn't work, a characteristic it shared with the new AVR circuit board when we came to try it, as it would not produce more than about 18V from the dynamo. On the plus side, Andrew's experimentation with applying modern gloss paints by roller was paying dividends, with Libby's cab sides displaying an excellent deep black finish, glossy enough to see yourself in.

In the short week that intervened we began to get the crew training planned for 14 901, for although it is getting on in the season the loco will be rostered by Peak Rail before the year end, so the operating manual received a further review and update. We popped back in to Rowsley on Wednesday evening though. Rob had reported that “Charlie” would not start, and as we had not had time to recover one of the Matterson brake units over the weekend, we dealt with both, although Charlie's main problem is that it is getting near to requiring some real TLC.

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On Saturday we headed back over to Scunthorpe. “Tom” had been parked inside the shed and armed with a quantity of jacks, Andrew, aided by Toby and Stephen, raised the left hand side of the loco up and extracted the leading spring hanger from the middle spring. This is one of the 2 we have identified that should be used with the 12 leaf spring, not the 14, and Andrew's plan, as a temporary measure, was to strip it out and clean it ready for replacement in due course, but for the moment replace it without the shock absorbing washer, which would give sufficient clearance for the hanger to be set to the same heights as the adjacent ones. It might seem unnecessary to go to the trouble of removing it completely, but the Sentinel spring system is a trifle unique, as instead of the solid pin one might expect, the spring and hanger are united by a tube, with end caps, all held together by a 5/8 whit through bolt. The centre section tube though, has a reputation for seizing in the hanger or spring eyes, and cannot be drifted out as there is insufficient clearance to the frame. But Andrew was lucky with this one, and having coated everything in copper-slip it went back at the hanger setting appropriate. A quick check with buffer beam clearances at each end suggested it had gone the right way, but there is no substitute for running the loco up and down to get the suspension to settle in to its preferred position.

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At the end of this, a further check of beam clearance (not an ideal way to checking, but a quick guide) suggested that it was significantly better (and watching the lead left spring suggested it was taking more weight) but the other side needs treating the same as the lead hanger on the right hand side is also for the wrong spring. There was no time to do that though, and instead we indulged in speculation as to alternative courses of action to get all 6 wheels to take the same weight, possibly hiring in some strain gauges for the purpose.

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Now, I wasn't standing back and supervising all this. I had retired to D2128 to start on some of the outstanding jobs there. First off one of the 3 limit switches that will control the powershift did not, you might recall, correctly function from the new cam and I had experimented in finding an alternate angle where it did. I therefore back-marked the new locating hole positions and re-mounted the switch, satisfying myself that it all worked and for the moment at least, we do not require any detente springs to hold the gearchange in first gear position.

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For some time now D2128's gearbox has had electronic sensors mounted that should detect the piston crown and thus which way the gearbox is selected. (I say should, because in the past I have always covered my posterior by drilling and tapping the piston crown and putting and M6 bolt in there as a target for the sensor, but this time I am trying it without. The shape of the piston may not give enough 'mass' to get a clear detection, but we shall see). Anyway, these sensors are not designed to switch significant loads and so I planned electronic relays down near the 'box for which a small enclosure was fitted some months ago. Conduit and cabling were now put in to place, though as the relay board is part built back home, not cabled up yet, and may wait until after we have got the loco to drive

Next on my list was to recover the relay levers for the handbrake linkage. The old pivot bolt was duly chopped through and the profiled levers extracted. But I could put it off no longer, it was time to squeeze myself up in to the front of the loco and swap the charge pump drive pulley. To recap, the front shaft of the engine drives two charge pumps, one for the converter and one for the powershift. Although I thought that I had recreated the volume/rev and rev ratio of the Hunslet original, one of the outcomes of the investigation into why we are not getting drive had revealed that the permissible leakage within the powershift is only marginally less than the pump should be delivering, and although our revving the engine up had made no difference, we ought to know that our basic delivery was on top of the job, so the driving pulley needed increasing in size and longer belts to suit. That one of the two required belts had disappeared in the interim, and my ordered replacement had not arrived, so I could not complete the job, but at least I could get the first part over with.

D2128 is sat on track whose rail heads are flush with the concrete floor, and although I am scarcely of a boxer's physique, I could only just squeeze under. In fact I wondered whether to remove my sweater to ease myself through. Off came the old pulley, on went its replacement and the one belt was fitted to check alignment.

That was pretty well it for the afternoon, but we prevailed on Toby and Stephen to assist in loading the MIG welder into the van so that it could go back to Rowsley.

Sunday, and we had to be down early as we were expecting Roger and Yvonne Wornham. Roger, being “Tom's” former owner, was claiming to feel guilty over our springing issues – unnecessarily in our view – and insisted on donating a few spare spanners to augment our collection of fine forgeries (as in forged hardware, before you get the wrong idea). Steph joined us and together we wandered around the various locos in the collection, discussing our plans and progress since he was last up.

Once they had headed on we set up the MIG welder down in the workshop and I lined Andrew up with the various materials awaiting welding, from the Mk2 relay lever for D2128, through to handrail stanchions and compressor frame for “Cheedale”. It was at this point we realised that we had not brought the chop-saw to trim the hollow sections to length, and outside on the A6, the traffic queues heading for Chatsworth's Country Fair meant that any idea of popping back to collect it would have occupied over an hour. So the compressor frame must wait for another day, but bits for “Cheedale” are at least on the radar.

For myself, I was back to Ashdown, firstly to instate the conduit tee I had bought from Sheffield on Friday and then trial an adjustable voltage regulator that gave better results but still not right, and later, with a bit of help from Andrew, exchanged dynamos with another, which we opened up and converted first, just to make sure that the problems weren't due to a duff one. Yet another regulator gave us some charge to the batteries, but for the moment we have left it off whilst we figure out what we need to change. Peak Rail staff are keen to get Ashdown into use, so it will probably get added to forthcoming driver training!

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Above all this were were serenaded by the Red Arrows as they screamed overhead to and fro for a display that visitors to Chatsworth may have paid-for, but we got our part for free.

“James” had not been run for a few weeks so we fired it up, luckily so as the batteries were a little tired, and Andrew insisted it was raining several minutes later until he ascertained that it was still spitting rainwater out of the exhaust.

As the day drew to a close we decided we really ought to get that ridiculous vac reservoir off Ashdown's rear. It came from a dmu and was effective at quick brake releases in stop-start suburban use, but was really unsuited to a loco. Moreover, as we started cutting through the straps that held it, it became obvious what a poor installation it was, as various securing welds had failed, and the whole arrangement had no tensioning bolts to clamp it properly (had it done so, of course, the few remaining welds would have failed sooner). The tank is now off, but its frame remains (with 6 tabs to bolt it down to original bolt-holes, but only 4 actually lined up) and will be headed for oblivion in our next round-up of scrap.

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Alas, not yet in the scrap bin is the existing format for Weekend Rails. Conversion of the posts into the new site is proceeding, but has been delayed by a further hack-attack on Andrew's site (which, I am told, involves dubious websites ostensibly in Spain and Florida but more likely Russia or the Ukraine). Repairing the damage, blocking IP's from whence it came and identifying other files that should not be on the server is still on-going and has subtracted from time getting the new-look WR finished. Maybe next week..


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