Steam Department

The second weekend of Thomas and temperatures into the 90's predictably led to a slower work day at the steam shop.  However we are now seeing more clearly that work is shifting to the new phase of preparing for reassembly.

On 1630:

·         On Monday I met George, the welding specialist from Curtis Boiler, on site and he carried out the welding on the rear tube sheet.

·         As mentioned in previous, weeks this was the last critical step to be ready for internal inspection of the boiler by the FRA.  With this done, Collin spent Saturday morning cleaning and clearing tools from inside the boiler as well as carefully inspecting all the surfaces for any sign of cracks or damage and polishing any rough edges from the tube holes.  We can now advise the inspector that all is ready for inspection and hope that he will be able to fit us into his schedule in the near future.

·         Glenn and Richard did some rework on the safe ends for the super heater flues.  Inspection on Monday indicated that a couple of these had been cut from tube that was more pitted than desirable so new ones were made ready for welding to the flues in the next couple of weeks.

Glenn cuts the taper on a safe end

·         A good start was made on cleaning and preparing the nuts and bolts that secure the super heater elements to the header.  This is typical of a lot of work that we will be doing in the next few months.  These bolts fit into the header at the top of the smoke box so have a tough life, in the path of the exhaust gases from the fire.  To remove them required heating to red heat with the acetylene torch.  Now they must be thoroughly cleaned, the threads checked and re-cut as necessary, to ensure that they fit and tighten smoothly when we come to fit the elements.

Element securing bolts as removed

and after a good deal of TLC

·         Vince cleaned and lubricated and number of the flexible stays ends so we are now well on the way thru that process.

·         Kevin is back for a few days and continued with needle chipping the exterior of the boiler and support brackets so that we will be able to do a thorough re-paint.  He is at Union for several days so this activity will continue during the week.

·         Mike continued with test fitting of the patch.  This is a very tricky exercise, a sort of three dimensional jigsaw.  It looks as if we are now close with this test.  Once this is done, we will run thru a second test to prove that the principles developed can be applied reliably to and then we can hopefully produce the patch proper.

·         I worked with Tom on preparations for fitting the tubes to the boiler.  This is quite a complex, multistage, operation that you will hear a lot more about in the next couple of months!.  The first step of the process is to expand the ferrules (copper rings) fitted between the tube and the rear tube sheet into the holes before the swaged tube is fitted.  After working with the various sizes of ferrule that we have been sorting and measuring for the last couple of weeks it is clear that we have nowhere near enough of the most commonly required size.  We will determine in the next week if we can get ready made ferrules this size in a reasonable time.  Otherwise we do have the right size of copper tube and will need to start cutting about 200 of these little rings !!.  Good news, it is now clear that, once you know how to match the ferrule size to the hole, the fitting process can be rapid.  After all the measuring and testing I was able to fit the first 5 ferrules in no more than 10 minutes.  This is likely to be the pattern throughout this operation.  We know that years ago re-tubing a boiler was an remarkable fast process.  We will have to become familiar with each of the steps and then try to become efficient but accurate at carrying it out.

On 428:

·         Machining is speeding up on the axle box thrust bearings.  The first one is complete and the second nearly so.

Thrust bearing largely machined from a second axle box

Interesting.  The attachment to this box looks quite different from the first.  This seems to be a common factor with 428.  Each part has been differently repaired at different times.

Nigel

The number of volunteers at the Steam shop was lower this weekend as it usually is during Thomas weekends.  However some key tasks were completed.

On 1630:

·         The last of the troublesome smoke box bolts was removed.  With the bolts out, I was able to clean up all the holes and test fit new "T" bolts into all of them bar one.  The new bolts are now being ordered for 10 of the 11 holes.  The 11th requires more work.  The smoke box has clearly been reinforced since this one was fitted so a rivet is now positioned that prevents setting the bolt into the ring from the rear.  Tom will need to make a special stud that we can fit from the front and secure by welding a nut on the back.  However, this repair is now largely complete and ready for when we refit the smoke box front sheet.

All the problem bolts are out !!

·         All the flexible stay caps, that were marked as requiring removal, were successfully freed.  This requires heating the socket of the stay with a torch before unscrewing the cap.  Applying brute force to the socket wrench without using heat to loosen the thread is absolutely not recommended!.  Cracking or otherwise damaging the socket would mean that the whole stay must be removed by drilling it out of the inner firebox then rethreading and fitting a complete new stay - several days of work - so it is a big relief that all are now off with no damaged sockets.  One damaged cap was successfully removed and will be replaced with our last spare cap.  A few more will be ordered to ensure that we have some spares in hand.  The caps must be removed and the stays hammer tested where the stay does not have a full length tell tale hole.

All the caps to be removed are paint marked

Once the cap is removed you normally find rust, scale and debris that must be cleaned out to allow later hammer testing.

There is normally debris in the socket

Once clean you can get a good idea of how the stay operates.  In the center is the ball head of the stay, a long steel rod the other end of which is threaded into the inner firebox sheet  The slot in the ball would have been used when the stay was installed to turn the rod and so screw it into the inner firebox sheet.  The ball sits in the socket, which is welded to the outer firebox sheet.  Screwing the rod into the inner sheet tightens the balled end of the rod against the socket. 

As with rigid stays, the objective of the flexible stays is to hold the inner and outer firebox sheets together against the full pressure of the water and steam that lies between the sheets when the boiler is in service.  The difference is that flexis are used where it is calculated that there should be (marginal !) movement between the two plates as they expand  This would strain and potentially crack a rigid rod.  The movement of the ball in the socket allows this movement.

Tightening the ball into the socket provides a significant, but not complete, seal against the boiler pressure so the cap provides the final seal.  This is why there is likely to be some debris in the socket when you first remove the cap.

The socket cleaned ready for testing

·         Mike continued with test fitting of the patch.

·         We also started on the exercise of measuring the holes in the tube sheet and matching these to the ferrules that must be fitted before the tubes can be inserted.

·         Most importantly, it now looks as if we should have good news on the welding by next weekend.

On 428:

·         Machining is now well under way on the thrust bearing surface of the first axle box.

First axle box mounted on the turret lathe

This clearly shows the remains of the old thrust bearing which consisted of mesh (actually old spark arrestor mesh from the smoke box was specified in the UP drawing), which was tack welded to the face of the casting and held in place the babbit which was poured into the recess, allowed to set and then machined smooth.

·         The overhaul of the pump mechanism for the planer was completed.  The next step is to clean and test the hydraulic drive mechanism.

The hydraulic pump now ready to refit

Nigel

A short and late update this weekend as I was in Michigan for my son's wedding on Friday.  This did at least mean that we had smaller groups working both Saturday and Sunday.

On 1630 work continued on the key tasks:

·         Between the two days we managed to remove 5 of the fireman's side smoke box bolts so we now have 10 of 11 out and have started to source the replacements.  None have shown any sign of moving when hammered.

So now we first cut off both the exposed thread and the head of the bolt in the smoke box:

Phil grinds off a bolt head

Then we have to drill most of the bolt core away with a magnetic drill.    

Mike and Gemma drill out a bolt

Only then can you drive the shell of the bolt out with an air hammer.  Heaven knows how these were fitted - but they sure were not intended to come out again !!

·         Jason completed a full review of the flexible firebox stays and marked those where the caps must be removed for inspection and hammer testing.  Most of these have been done leaving about 20 for next weekend.

·         The pipe to replace the corroded lines down the side of the boiler has arrived and marking up to bend and connect the replacement sections can now begin.

·         With a family visit on Sunday, my wife spent much of the day sorting our supply of ferrules into sizes and removing those that were damaged. 

Sorting the stock of ferrules

These ferrules are a critical part of the re-tubing process.  They are copper rings that are fitted in the rear tube sheet between the sheet and the tube when it is expanded.  From initial count it looks as if we may have all we need but will need to match them up to the tube sheet in the next couple of weeks to determine if we need any more.  The key objective is to ensure that we have all that we require in hand before we get to tube fitting.

·         Unfortunately we seem to be having difficulty agreeing a start date with the welding contractor who needs to finish the work on the rear tube sheet before we can schedule the internal inspection of the boiler.

On 428 the machining of the axle boxes was started.  The first box is now on the Bullard turret lathe and the process of machining off the lateral bearing has begun.  The intent is to fit brass wear plates similar to those on 1630 rather than the poured babbit used on these boxes in the past.

First axle box mounted on the turret lathe

Bob came by with the newly fabricated collar for the wheel lathe that now needs just final boring to be ready for fitting.  With this critical piece in hand we are a major step nearer to being able to bring the wheel lathe into operation.

Nigel

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