Sunday, 14 February 2016

Maintenance Update (pony again, pit, bearings)

Monday 8th
Bruce had emailed me and mentioned that it would be a good idea to check the gap on the rubber shock-absorber housing. The gap between the bottom of the top “cup” housing and the top of the cover plate over the axleboxes should be about ¾ inch. Before taking the pony out, the gap was different on each side, at somewhere around 0.8 inch and 1.1 inch. When the pony was assembled, but before it went back in place, the gap seemed to be over 2 inches. So, Bruce had removed two of the rubbers.  Now the pony is in place and with a weight of nearly 6 tons on it, what is the gap?

That on the left side is ¼ inch; that on the right 1/10th inch. Not acceptable! Pony has to come out, again, and have its rubbers re-inserted! Much debate has been had on compression of rubbers, etc.

Having tidied up on Saturday, I now spent a couple of hours un-tidying again! Tried to prepare (to some extent) for Wednesday. But having practiced removing and refitting the pony, it will be easier this time …

Tuesday 9th
I spent a couple more hours preparing for Wednesday, by positioning jacks; removing pony pivot pin; propping up the whacking great front-back beam; disconnecting the heavy weight in front of the smokebox, and raising it to clear the pony, below. For an encore, I wire-brushed the faces of the LHS valve cover, in readiness for it to be refitted.

Wednesday 10th
The whole team (Gil, Bruce, John G, John T and Graham; plus Mike later) focused on getting the pony out again; fixing the rubbers, and getting it all back together.

Mostly, Bruce & I were underneath somewhere. This photo was taken by me, lying down under the pony, with Bruce guiding the pony frame back into position. The frame end fits into the bridge piece and is held in place by the pivot pin.

The whacking great beam balances load on the loco front springs and the pony truck. Bruce had made more calculations about rubbers and their compression. We all agreed to replace the two rubber discs that had been removed, but to take out two metal plates - one from each end of the stack of rubbers. This should increase the gap (that ought to be about ¾ inch) from the current 1/10th on the RHS to about 5/8”; and the LHS from ¼” to about 1”.

So, when the pony was out (lunchtime) the rubbers were refitted and the pony reassembled. The details would be much the same as last time (so I won’t repeat them).

While Gil was preoccupied, John T fitted a PTFE gasket to the valve cover, and at a subsequent stage, I fitted it back in place.

John G, John T, Graham and Gil were predominantly applying their muscle power to rolling the pony out (initially) and back in. In the photo below, the pony is back; the weight has been lowered and connected to the beam. John is here inserting the pin to lock them together, plus fitting the cotter and split pin to secure them.

Jeff L was passing by and spotted that there were no corks in the oiling points on the pony axle boxes - the sort of thing that only a driver notices! He kindly brought a handful out and fitted these four.

By end of play, we were back to where we were last weekend!

I must pass on our gratitude to the Loco Dept chaps who have been beavering away on our tender. They have fitted new brake blocks all round.

Workshop Graham drilled the blocks’ pivot position to suit, and then a team of chaps set to work. Apparently, they had got it down to 2 minutes 59 seconds to fit a brake block. Where have they learnt their skill, I wonder???

One bit of fun was at the front RHS, where a bolt had to be removed to adjust the brake setting. It seems that we had fitted it the wrong way round (sometime during the 1990s). To get it out and turn it, necessitated playing with the water scoop. However, the GWSR Mechanical Responsible Person had insisted that the handle be padlocked to prevent anyone from ever lowering the scoop while in service. Guess what? No one knew where the key was! Bolt cutters persuaded the padlock to let go.

Thanks go to Clive, Mike, Martin, Alex … and apologies to others that I have missed.

Thursday 11th
I spent a few more hours down there today, tidying up the front LHS of the loco.
  - Front valve cover is on and tight;
  - Cladding is on around it;
  - Running board is on above it.
That took 2½ hours!

Friday 12th
Bruce reports:
“I popped into Todders today to trial fit the underkeep bolts that I have modifying. I breezed into the shed rear door and nearly fell over, no, not drunk, but no loco.

I found it at the far end over the pit with our tender behind it, there is a gap between them so that we have access.

Carpo had shunted it earlier in the morning. He said that it came with a deal. The deal was that we cleaned the pit (and probably the oil that we had left on the floor at the other end too).

While I was there I took some quick measurements of the gap between the spring housing and the axle box to see if it had changed during the move.

The LHS gap was the same at approx. 1 inch but the RHS had dropped slightly (almost 1/16") to just under three quarters of an inch.

I got the trusty spirit level out and it confirmed that the RHS was slightly low. It was not far out and only needed one of our 12" rules laid flat under the low end to bring it level (didn’t measure the rule but I would guess that it is about 1mm).

I guess that it may change again when the boiler is full.

Saturday 13th
Family commitments kept me away, but John T reports:
“Bruce cleaned up the hanging link outer face to get the new pin almost hard up against it. He worked on setting the pony truck journal bearings hanging tee-bolts (that hold the under-keeps) so that they could be properly fitted to the under-keep straps with the split pin after the nut, not through it as before. He also spent time improving the sealing face of the first under-keep drain plug.

David worked on preparations for fitting the new tender to engine water hose bosses. This involved removing existing connections and preping and welding new flanges which will take the new bosses currently in the machine shop.

Gil and John T worked on reaming the second (of 4) fixing bolt holes for the RH hanging link bracket, to take one of the new fitted bolts. Slow work, as the reamed hole needs frequent checking to achieve the correct amount of interference fit for the new bolt. What a relief to drive the bolt home! They then fitted the hanging link, which because of its weight, needed help from Bruce and David to get it lifted up into position on its (running board) bracket.”


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