Steam Department

The high temperature and the number of visitors associated with the Union Pacific family day meant that work was a little more subdued than usual this weekend.  However some significant progress was made.

On 1630 the main focus was on investigating the back head braces.  As discussed last week, the drawings, which have been the basis for previous calculations, suggest that this is the most highly stressed area of the boiler and potentially limits the pressure at which we can operate.  For this reason we worked on ways of measuring how big the braces really are.  This is no easy task as the critical braces are above the inner firebox 6 to 8 feet back between rows of stays that are only 4 inches apart.  The picture shows the area braced.  The position of the attachment bars is marked in chalk and, within these,  the circles show the attachment points of the braces.

This shows the area braced

The method developed relies upon using a rigid steel "fork" that is strong enough to break scale off the brace and marginally less that 1 3/8 inches across.  This will just fail to pass over a 1 3/8 brace but would easily pass over the smaller 1 1/4 or 1 1/8 (the 3 sizes shown in the design).  This was proved and tested on the front tube sheet braces, which are very similar but easily accessible.  Most of the team supported Jeff and Phil to develop a rig of webcam and lighting that could be fitted between the stays to observe and record the fork being applied to braces hidden above the firebox.

Whilst painfully slow and hard work for the guys, particularly given the heat, the results were very encouraging.  The first two of the hidden braces we have reached are definitely NOT the smaller 1 1/4 size shown on the drawing but 1 3/8.  So we can already say the bracing is stronger than drawings would suggest.  The bad news is that the remaining six braces are even more tricky to get to!!.  Phil made a second test fork shaped to give us the best chance of reaching these and we will continue next week.

The fork would be an easy fit on the 1 1/4 brace

The shot above is the result of this process.  This is about 7 feet along the length of the firebox but clearly shows the brace and the measuring fork.  The fork would be an easy fit on a 1 1/4 bar and just fails to pass over a 1 3/8 rod, so this is clearly larger than the drawing shows.

(In case anyone is wondering why a difference of 1/8th inch is so significant, the stress is related to the cross sectional area of the braces so the difference in area and reduction in stress between a 1 1/4 and 1 3/8 brace is a full 20%).

Mike, Bob, Ed, Stu and others continued drilling out the rivet holes for the firebox patch.  This is now approaching completion.  All the holes are now pilot drilled and are being steadily increased in size to create the exact size required for the rivets.

Mike and Ed drilling out rivet holes

We received the steel bar needed to produce the piston rod for the McCabe and Bob set that up in the lathe to start the machining to produce the piston rod.  Once the McCabe is repaired we can start work on the patch itself.

Glenn repaired the Sullair so we are now ready to sand blast the tube and start work on the safe ending the super heater flues.

Stu and Bob worked on assembling the hydraulic pump for the planer.  This will be a powerful tool if we can bring it into service.  The table moves back and forth thru the cutting head allowing several large items such as axle boxes to the machined consistently and simultaneously.

The planer under refurbishment

Stu and Bob reassemble the hydraulic pump

Phil and I collected the new cab windows for 2050 that have been made in the woodwork shop.  These are beautifully made and will really improve the look of this impressive locomotive.

.............. Don't forget the Steam department benefit at Sanfillipo on July 1st tickets are available on the main web site.

Nigel

At least I was able to get back to Union this weekend although mainly as a nuisance to others as I cannot lift anything much!!.  Some key milestones were achieved.

On 1630 we reached the important milestone that has been our objective for several weeks

·         All the measurements of boiler sheet thickness for the form 4 have now been completed.  We owe an enormous thank you to Tom Huber of ECE Global who spent a second day crawling in and over the boiler with the UT testing equipment to complete a comprehensive set of measurements of every part of the pressure vessel.  Collin, Phil and several others from the team supported him in locating points, cleaning and recording.  We now just have to plot all the final measurements on diagrams of the sheets to complete a major part of the form 4.

Tom and Collin testing in the firebox

With professional equipment a lot of points can be measured quickly

Crawling in the boiler to test the dry pipe

The shell itself is easier

Many thanks to Tom for all his efforts

·         Dennis cut back and welded a small crack we found in the dome lid securing ring.  We had been wondering how a crack this shape could form and now we know.  It resulted from a small inclusion (defect) in the casting when it was made 95 years ago !.  So it is now better than it has ever been.

Dome ring now made good

·         The flexible stays where the caps have been removed were thoroughly cleaned and are now ready for hammer testing;

·         A lot of progress has been made toward safe ending the super heater flues. 

A rigid measuring bar was made from used boiler tube to allow exact lengths to be confirmed;

Making the measuring bar

Glenn Traced the problem with the Sullair to a broken fuel pump so we can hope to sand blast the material needed for the safe ends once the replacement fuel pump arrives next week;

Phil and Cameron have made substantial progress on chamfering the ends of the flues to accept the safe ends;

One flues that was found on inspection to have an existing weld was shortened to allow a new end to be fitted.

Cutting the tubes to length

·         We will probably do some work over the next couple of weekends in an attempt to clarify one anomaly.  1630 has been restricted in recent years to a 160 psi boiler pressure as opposed to the 180 at which it ran during its service with the Frisco and Eagle Pitcher.  The reason for this is not wear but an apparent anomaly in the design.  Drawings of the boiler consistently show the back head braced by a mixture of 1 3/8 and smaller diameter 1 1/4 diameter braces.  The reason for this is unclear as, even by the standards when built, inclusion of the smaller braces brought stresses at 180 psi close to the limit in this one area when all other areas of the boiler show substantial reserve.  

As shown a couple of weeks ago, these braces, particularly the ones shown in the drawing as 1 1/4, are extremely difficult to access.  However, yesterday for the first time we did manage to get a measuring tool to one shown in the drawing as 1 1/4.  The strange thing is that it does not appear to be smaller.  So the big question we will try to answer is whether the braces are actually bigger than the drawing shows.

Paul reached a milestone on the truck for the Shay.  This has now been needle chipped to the point at which we should be able to give it a final application of degreaser then a final steam clean and be ready to inspect and repaint.  Given the large number of visitors to be expected next weekend for the UP event, steam cleaning will be scheduled two weeks out.  This is not something you would want to be doing with many visitors passing by!.

Needle chipping reaching the end

Nigel