Illinois Railway Museum Blog

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