Steam Update December 2015

Another year draws to a close and there is a lot of activity in the steam shop.  I had expected the day after Christmas to be fairly quiet but there was a good turnout and work proceeded on many fronts.

On #1630 we are progressing along what is now the standard plan for the Winter with the normal annual inspection work, which is substantially boiler focused, running in parallel with “catch up” work to improve the overall mechanical condition of the locomotive.

Aside from some smaller items, the major focus this Winter is on the valves.  It has been apparent for some time that there is wear in the valves leading to lower efficiency and leakage that can be demonstrated when the valves are set in specific positions with steam applied.  As with most backlog work, the initial hope that we could get away with a quicker and simpler repair has proved sadly misplaced!.  Guess we should not be too surprised.  When doing the initial stripping we found some tags set behind the valve chest nuts that indicate when last stripped for overhaul – SLSF Springfield shops 1947!.  You really have to question the quality of the work when we have to do it again after only 68 years!!.

The findings so far are a mixture of good and bad news.

The valve chests have liners in which the valve spindles run.  These are press fitted to the casting at each end and the ports leading to each end of the cylinder are in these liners.  In this view of the ES valve cylinder with the valve removed you can see the front liner including the ports with the live steam chamber behind it (and the rear liner and ports behind that)

Inside the valve cylinder

The movement of the valve, which has sprung rings bearing on the liners, opens these ports to the steam supply (center) or the exhaust (outer ends) as the spindle is moved back and fore by the valve gear.  Wear on the rings and/or liners results in leakage and deteriorating performance.  Here you can see the valve itself.  In use the central section feeds live steam while exhaust steam is released ahead of and behind the outer faces of the valve body.

ES valve spindle

Here the rear of the ES valve cylinder shows the space where the valve spindle has been detached from the crosshead and removed from the gland but the crosshead is still attached to the combination lever.

Crosshead with valve removed

Then the crosshead was detached from the combination lever and removed.

Crosshead split from combination lever

The initial hope was that the problems might be corrected simply by fitting new rings, of which we do have a substantial supply acquired with the locomotive.  Bad news.  Having opened up the valve chest and measured the bores, which should obviously be perfectly round, they are worn out of round to levels significantly outside acceptable tolerances.  So replacing the rings would not be expected to fix the leakage.

The next standard level of repair is to re-bore the liners.  Here the news was good.  On these locomotives the liners start at a 12 inch internal diameter when new and can be bored in 1/16^th increments to a maximum of 12 3/8 inches, at which point new liners are required.  It looks as if #1630 must have received new liners when the job was last done as one measures 12 inches and the other 12 1/16.  So this says that, unless we hit unexpected problems in the boring, we have plenty of metal for a cut of 1/8 or 3/16, which is the current estimate of what is required to bring the bores back to round.

Yesterday the stripping continued.  The yolk that supports the valve crosshead on the back of the ES valve cylinder was removed.  Sounds easy but this thing is a solid lump of steel !.

Crosshead yolk removed

With this removed the rear end of the cylinder and the liner are clearly visible.  A substantial number of the studs came out of the casting rather than the nuts coming off the stud.  Not altogether surprising.  In 70 years exposed to steam and heat in this position the nuts were heavily rusted to the studs.  This is now substantially ready to start mounting the boring bar that will be used to re-bore the liners. 

Looking into the back of ES valve cylinder

Work has started on preparing the boring bar that is required to re-bore the valve cylinders.  This is a huge piece of equipment in its own right.  Luckily we have a full set of this equipment although it has not been used since the cylinders on #428 were bored in the 1980's.

In parallel with the valve work, a lot of other tasks have been progressed.

Lots of unpleasant and dirty work has been done in clearing the tell-tale holes in the stays as part of the annual inspection.

Phil has been working on ensuring that all the wedge bolts are free and working correctly.  At the moment this is more in preparation for the program for next Winter when we hope to do a full check on the alignment of the drive axles.

The spring loaded buffer between locomotive and tender has been removed and inspected.  As suspected the heavy springs that take up the slack are slightly compressed with the result that there is a little slack apparent on the footplate as you start to reverse.  This is being corrected by adding some spacers that will ensure the buffer always retains contact between loco and tender.

The stoker discharge / fire hole door casting has been detached in preparation for remaking the fire cement seal between this and the fire box.  Some smoke and fume could be seen leaking thru this joint during last season.

The FS injector starter valve has been removed for machining of the valve seat.  This has been subject to repeated minor but annoying leaks and has been lapped a number of times.  Hopefully re-machining the seat will give us a more permanent repair.

On the Shay, work proceeds steadily.

Probably the most critical aspect is temporary work.  Dennis has been fabricating steel  backing plates that will provide a rigid surface against which the bucking tool can be braced to allow the rivets for the smokebox to be formed.  These are critical as a number of rivets must be driven in locations where there is not sufficient space to brace manually.  (These are rivets that would normally have been driven with the boiler at least lifted if not completely out of the frames).  This is a critical step as, once the rivets are in place, a whole bunch of other work can get under way.  Aside from the obvious work on the front end, once she can be taken off the jacks, it becomes possible to reconnect the tender and third truck.

Supports for rivetting

A lot of work has gone into needle chipping the firebox so that this can be properly painted.

Work is well under way on setting the wires around the boiler to which the insulation will be mounted.

Wires to attach insulation

Jane has been hard at work on removing rust from the back of the boiler cladding and then painting this.  At this point she will look a lot better INSIDE the boiler cladding that outside!.  Brian is planning on doing a really good paint job once she is complete so only the hidden areas are being painted for protection at this stage.

On #428

The cab riveting is now complete and work has moved on the filling the last holes and then painting in preparation for making the wooden cab lining.

On shop services, the large compressor is now fully plumbed in.  As soon as we can get the power connected to it we can test and adjust it ready for the state inspection.  With luck this will be ready when we want to rivet the smokebox of the Shay.

So a lot of activity but a whole lot more to be done if we are to be ready for running at the start of the season.  So, Happy New Year to all and watch this space!.

Nigel