Steam Department

It was one of those days when casual observation could suggest that the steam department had done nothing !.  However we made steady progress on some critical work although the visible effect does not look much.

On 1630:

·         we have now agreed terms with the boiler welding specialist for the back tube sheet and super heater flue work.  Hopefully that will be done shortly.  It should only take 4 days once he is on site.

·         the pipe to replace the corroded runs along sides of the boiler has been located and ordered.  This in itself gave some quite surprising results.  The small diameter heavy gauge steel pipe used on a steam locomotive now has few uses and is made in small quantities.  Price is therefore driven by batch sizes and availability rather than the weight so we have larger tube costing less than larger and seamless costing less than seamed in some cases.

·         Collin finished the inside of the front tube sheet, so internally we now only have the contract welding of the rear tube sheet to do.

·         Mike and Bob continued forming the test sheet for the firebox patch.  The activity this week was focused on forming the shape to match the sloping front tube sheet while retaining an accurate match to the curve of the mud ring.

Mike shapes the test patch

·         the major activity was the continuing battle with the smoke box bolts.  These apparently insignificant 3/4 inch bolts occupied a number of us all day.

Looking at the locomotive in service they are simply the bolts onto which the nuts, that you see in a circle around the edge of the smoke box front sheet, are threaded.

What we are working on

Although they appear at first sight to be studs, they are actually "T" headed bolts, unthreaded in the length that passes thru the front ring, that are driven into the ring from the rear.  The snag is that they cannot be a really tight fit on the front sheet so there is a hidden cavity behind the nut in which moisture and gases attack the bolt.  In service the smoke box is under vacuum and any leakage causes loss of efficiency and rapid corrosion as air is sucked past heated metal.  We want to ensure that, once we do this overhaul, we have reasonable confidence that 1630 will be good for the next 15 years so we are working on the basis that these bolts should be replaced where they are wasted to less than 5/8th inch.  This means removing 11 bolts.  It is clear that the bolts at the top and bottom, which are subject to greatest wear, have been replaced at some stage as most of the 11 are at the sides.

The documented way of removing these bolts is to hammer them from the front, potentially having heated the ring to assist the process.  The bolts on 1630 do not seem to have heard of this process !!.  None have proved possible to hammer out anything like whole.  They are so firmly in place that hammering expands the bolt in the hole and makes it impossible to remove.  The technique evolved during the day is to grind off the head of the bolt (which we think may in some cases have been welded during repairs at some time), very carefully drill a hole centered  on the bolt and enlarge it to allow an air hammer bit to be inserted.  This allows the air hammer to be used with less expansion of the bolt.  If this does not work you have to collapse the sides of the bolt into the hole, re drill and try again.  We now have 5 out.  They are very variable.  The last and worst did not come out until we had done this multiple times and reduced the length for 2 1/4 inch to 3/4.  The huge frustration is that, when they eventually come out, it is just a plain smooth plug with nothing to indicate why it would have been so difficult to move.

Drilling the last one on the engineers side

Here you can see the bolts.  The green paint marks indicate good.  The red marks and gaps those that are to be or have been removed.  Here we are working on the last one on the engineers side, which proved to be the worst so far.

Late on we called in reinforcements and received full support from the IRM Board.  Thank you Jim !!.

Jim working on a steam engine - one for the records

Any way , 6 more on the fireman's side for next weekend, then we can think about putting in the new ones.

Finishing the engineers side

Elsewhere Phil removed the lugs from the back of one of the axle boxes for 428 so that it can be mounted on the Bullard turret lathe to machine the bearing face.  The plan will be to fit brass bearing faces, similar to those fitted to 1630, rather than poured babbit faces previously used.

Phil prepares one of the axle boxes for machiningWhat we are working on

I will not be at Union next Saturday as my son is getting married.  I do hope to be there Sunday so hopefully I will be able to report on a lot that the team has been able to get done without me getting in the way!.

Nigel

Another good week in which we were able to move a lot forward on 1630.

Various tasks support the overall work plan.  First we must finalize preparation for the inspection of the boiler shell.  Not much remains to be done to enable this so the next focus is on the tasks that will enable us to make the boiler water tight again.  For this, we are preparing all the flues and materials that we need to refit the tubes and also to complete the patching of the firebox.  Finally, whenever possible, we work on ensuring that parts that can be fitted once the boiler is watertight and passes its first hydro test are cleaned and ready to be fitted quickly when required.

·         During the week Jeff and Jerry managed to complete the cleaning and hydro testing of the super heater elements.  The conclusions were good.  24 passed the pressure test at 1000 psi with no issues and are back in the box car ready for refitting when the boiler is ready.  1 passed the pressure test but has some minor damage to the protective shield (a simple sheet metal construction that is wrapped around the element to protect the most exposed areas from erosion by cinders flying thru the flue) and only 2 failed.  The last 2 will require the attention of the boiler welding specialist when he comes in to safe end the flues.

·         Phil and Collin cleaned up the front tube sheet in preparation for re-tubing.

Front tube sheet is now ready

·         Eric did a great job clearing the medium from around the firebox.  This is important so that everything is clear and visible for the upcoming inspection.  The blasting medium is deceptive stuff!.  We knew that there was some still on top of the firebox.  The initial comment in the morning was "don't think there's much there".  Having used an air line to blow it off the firebox crown and the stays at the sides of the firebox so that it settled into the bottom of the firebox water legs, Eric sucked it out with long pipes on the vacuum cleaner.  By end of day we have a clear view along the bottom of all the water legs .......... and probably 80 lbs of medium extracted !.

Eric removing blast medium from the water legs

·         After a lot of adjustment to get the settings right the McCabe was used to bend a test sheet for the firebox patch.  Past experience with the Shay has demonstrated the importance of proving exactly how the patch will be formed using an old piece of steel before we do it "for real" with an expensive piece of new boiler plate.  Considerable progress was made.

The McCabe was used to bend the sheet

Test plate loaded in the jaws of the McCabe

The jaws start to bend the plate

and bend it smoothly to the small radius curve

........... and the radius formed proved to be an excellent match to the critical curve in the mud ring.

The result looks a good match to the old plate

Having been cut to the template, the piece is a pretty good fit to the firebox and can be used to make minor adjustments to the template for the final patch.  The next step is to form the piece to fit the slope of the front tube sheet.

Mike holds the test plate up to the hole in the firebox

·         Ed and Jim identified and measured the pipe work to be replaced along the boiler and this can now be ordered.

·         Phil, Jeff and I started another job that looks like it will be a lot more "fun" than we had hoped!.  A number of the bolts that project from the front ring of the smoke box to secure the smoke box door sheet are wasted and need to be replaced.  In theory they can be driven out by hammering them back (towards the boiler).  In practice the effect of 60+ years of heat and rust on bolts that were a tight push fit to begin with is "interesting".  After 90 minutes of effort with a heating torch and air hammer we have one out.  Only another 15 or so to go !!.

·         Bob Hunter has now finished the computations and supporting documentation for the form #4 submission.  This is the engineering assessment of the boiler which confirms that, having regard both to original design and subsequent wear as now measured, it is suitable for the intended operating pressure.  This is now ready for submission.

Nigel