Steam Department Update February / Early March 2016

Another month of steady progress in the steam shop.  There is rather less detail this month as I was away for three weekends visiting family in the UK.

Obviously the central focus is on getting #1630 complete in time for the start of operations in May.  The regular work for the annual inspection continues in parallel with the major project of the valve overhaul.

The boiler and other work for the annual inspection is now largely done.  A couple of weeks back, Phil cleaned and checked the arch tubes.  After that the last of the wash out plugs were re-installed.  Yesterday the testing of the pressure gauges was carried out so these can now be re-installed.  The boiler will then have everything in place for the hydro-test.

We will now schedule this test with the FRA inspector.  Once this is done we can conduct the internal inspection and, subject to any issues detected in testing, plan on steaming.

Obviously one essential part of the annual inspection is correcting those items that are considered out of or close to allowable tolerance.    In this context, the spring loaded buffer on the front of the tender is was overhauled and the upper cross head bearing on the fireman’s side is being re-metaled.

The buffer has been cleaned, spacers made to take up the slack in the springs and painted.  Yesterday it was re-installed onto the tender. 

Tender buffer back in place

The tender is now complete and all that remains is to re-couple it to the locomotive by refitting the main drawbar.  This has been removed, thoroughly cleaned and inspected for any cracks as required for the annual.  Recoupling will be done as we prepare for steaming as this is best done by pulling the tender out of the shop and lifting the drawbar into place outside, where we have space to use the fork-lift.

A big job completed recently was casting the new Babbitt bearing for the crosshead.  What does this mean?.  Babbitt (alloys of tin or lead with copper and antimony) has been used for nearly 200 years to create a bearing surface against steel or iron.  A favorable combination of relative softness, compression resistance and porosity, which facilitates the distribution of lubrication, mean that it is widely used for bearing surfaces to this day. 

However, while modern usage is usually as a thin layer in a backing shell of a harder material, the more traditional usage made use of another property, low melting point.  The metal melts around 400-500 degrees and casts well at 800-900 degrees.  It will adhere well to iron or steel that is treated with a flux but not to a dirty surface.  The principle is then simple.  One iron or steel surface, normally a casting, does not need to be machined and is over-size versus the shaft or rod that moves against it.  Molten Babbitt is then poured into the over-sized space in which it solidifies to form the bearing surface.

In the most basic form, the bearing is cast in situ.  A smoky flame is used to soot the surface against which the bearing will slide, any gaps thru which the molten metal could escape are blocked and the molten metal is poured in.  The contraction of the Babbitt as it cools provides a small clearance and the bearing should be ready to go with no machining necessary.

The bearing that we must replace is that in the top of the crosshead which bears on the slide bar.  In theory this could be cast in place.  However it was felt to be considerably safer and more accurate to cast the Babbitt in the crosshead shoe with some excess and then machine it to final size on the planer.

To do this the shoe, with a tray positioned in the center to make the “U” shaped channel, forms the mold. 

Jason adjusts the tray in the shoe

Shoe in furnace with mold in place

The whole assembly is heated in the furnace so that the Babbitt remains liquid when it is poured into the mold.  The shoe is tinned to help the Babbitt to adhere while the tray is soot coated to help it release after cooling.

Jason tins the shoe to make Babbitt adhere

Babbitt being melted in the second furnace

Pouring the Babbitt

Once the babbit had completely cooled, the tray was removed, the crosshead shoe was mounted onto the planer and Tom has started machining the babbit to its final dimensions.

Shoe in planer and bearing part machined

Meanwhile the valve overhaul has progressed well.

Both valve chambers are now bored to size and the boring rig has been removed.

Valve cylinder after re-boring

The valve rods were sent out to a specialist for surfacing to remove areas of wear that form over time as they run in the gland packing.  These are now back and ready to start the reassembly of the valves.

The four cast iron blanks to make the new bull rings have now been machined to final internal and outside diameters.  Needless to say, each of the spiders proved to be of slightly different diameters, so each of the blanks is now unique to one particular spider and therefore one of the four positions in the locomotive.  They have also been tested in the bores and proved to be the required fit on the external diameter. 

These are now off-site being machined to produce the finished bull rings.

Many happy hours have been spent in cleaning the spiders and valve bodies.  It is essential to remove the hard carbon built up on these but, each has a small lip that secures the spring ring.  So it is a long and careful process to carefully remove the carbon without causing wear to the lip.

Spider stripped and cleaned

In preparation for re-assembly the studs that hold the cylinder ends have been inspected and around 50%, that were excessively corroded, have been replaced.  This provided interesting confirmation of the history of #1630.  On the engineer’s side 15 of the total 20 required replacement but on the fireman’s side only 4 needed replacement.  This is explained but the fact that, in the late 1930’s, she was involved in a head on collision with a Mikado, suffered heavy front end damage, and the FS cylinder casting was replaced.  So the casting and studs on the ES are mostly 20 years older than those on the FS.

New studs in place and the hone in place in the cylinder

A minor set-back has been the conclusion that the bores need to be honed before the valves can be refitted.  As with many things in the steam shop, this needs unusual equipment.  Honing a 12inch cylinder requires a pretty slow turning motor.  While we have such a motor, it has not been used in many years and proved to need overhaul before it could be used.  That is nearly complete so the honing can hopefully be done soon.

Once this is done and the bull rings are completed, we should be able to start re-assembly of the valves.

Meanwhile work has progressed slowly but steadily on the Shay.

One major step is that the form #4, engineering assessment of the boiler has been completed and submitted for FRA review.

Most of the holes for rivets in the smokebox have now been reamed so we are getting close to being ready to rivet.

Phil has been working on fitting the grates.  This is a significant job as the grate assembly is new.  Prior to overhaul she ran with a less than satisfactory arrangement fitted when she was converted from oil burning.  This time she is being fitted with a new grate set up that should be more satisfactory ……………… once the new castings are carefully adjusted and fitted to newly installed bearers.  With a lot of work Phil has now got the grate bearers fitted and the grates themselves are now being test fitted.

Mike has been replacing some broken studs in the cylinder heads.

Jerry has been making good progress on lagging the boiler.

Jerry fits lagging to the boiler

Progress.  One complete section

Work has continued steadily on the cab for #428.  The riveting team have been making good a few final missing rivets.  Dennis has been filling holes and shaping the roof to remove a few non-standard curves that it had developed and John has been painting and fitting the window guides.

In the shop.

Collin has made considerable progress on the large compressor despite having to be away a couple of weeks on business.  (Two weeks at ore loading facility in Northern Canada in mid-winter.  Temperatures heading to -40.  He does get the nicest assignments!).  One damaged valve was replaced and he has made significant progress on lapping the other valves.  The compressor now runs much more smoothly, sucks intake air with considerable force and pumps the reservoir up to the 150psi operating pressure pretty quickly.

From testing yesterday, the reservoir safety valve operates correctly.  We were also able to identify two leaking gaskets that will need to be replaced.  Once these are replaced, the compressor should be serviceable.  Two other key steps were agreed.  Everything on the compressor is now installed enabling Dennis to finish and install the guards over the drive belts and the method for unloading air pressure to allow the compressor to start when the reservoir is under pressure was agreed.  Parts for this will now be ored3er and fitted while we wait for the replacement gaskets.  Hopefully we should be able to get to readiness for the system to be inspected in about three weeks.

There was sudden major movement on another long standing project.  The control cabinet for the wheel lather arrived.  John and Bob started to install this.  They have now identified exactly what parts are required for the low voltage control circuits so this is coming together at last.

We have also had donated an excellent large band saw that will be most useful in the shop.

New band saw is unloaded

So a lot of progress but still quite a lot to do for the start of the season.  Watch this space.

Nigel