May 2025 Update

By Pete Maddicks & Tony Howard. 

A bumper update this month as May has got off to a very good start with the completion of the cladding along the top of the water tanks. The copper delivery pipes up to the clacks are all but finished, and the steam fountain and all of the fittings that go onto it are ready for hydraulic testing. Tanks removed, boiler out and tanks back on. The boiler can now be completed, the steam test carried out and the ten-year boiler ticket can start. As you can see huge steps have been taken, but the biggest step forward was the removal of the boiler, which when completed the big push will be on, to get the locomotive finished, wasting as little of the ten-year ticket as possible.

This month, as promised I am giving a brief description of the operation of the vacuum retaining valve. This again is not intended to be a full engineering explanation, but a brief description for those of you who would like just a basic understanding of what the components of a locomotive do.

Vacuum Retaining Valve
The vacuum retaining valve is part of the brake system. Its job is to transfer the work done by the vacuum pump between the train pipe and the reservoir.
When the train is running normally the pump helps to maintain the vacuum in the train pipe, therefore saving steam as there is no need to keep the small ejector open. When a brake application is made the retaining valve automatically changes over so that the pump pulls on the reservoir side and therefore helps to maintain the brake on long descents.
(see photo 1).

This is again a brief description of the operation of the vacuum retaining valve, if you would like a more detailed explanation please refer to the Handbook For Railway Steam Locomotive Enginemen.

Tuesday 6th May. 
Bob L, Brian H, Dave L,  Dave Mc, Steve T, Tony H, 
We were told that there was a number of boxes of insulation material in storage, and we could use it on 4150. Dave Mc and Tony went to see how many boxes there were. There were 15 boxes of various thickness but mainly 50mm thick which is the ideal size for the boiler. The other sizes were 25mm and 13mm that are OK for the firebox.
Dave and Steve worked on the infill cladding for the left-hand tank.
Brian had finished more copper pipework and it needed hydraulic testing.
Dave Mc and Tony undertook this operation under Brian's supervision..
By the end of the day, all four lengths of pipe had passed the hydraulic test.

Saturday 10th May.
Jacob L, Peter M, Tony H. 
Arrived at Bridgnorth to find that there is a shunt planned to get a coach into the paintshop. This gave us an opportunity to get the loco onto the pit outside.
Jacob oiled up the loco and Tony had a look at the back end of the ashpan to see where the cut-out would be for the operating lever to operate the drop grate. Peter noticed that the felt pad that oils the piston rod was out of position. This was corrected and when the loco was shunted back into the shed it was oiling the rods evenly.

Monday 12th May.
Charles L, Dave L, Dave Mc, Peter D, Peter M, Phil H, Si B, Steve T, Tony H.
The Steam Fountain is almost finished, Phil and Tony opened up the four holes in the base, as the last time we temporarily fitted it we could only fit it on two studs. Using an adjustable reamer we opened up the holes a further 1/8" of an inch. It now fits nicely over the four studs.
The operating system for the drop grate was looked at, and a  decision was made about how to proceed. Four holes were drilled in the corners of the section that needs to be cut out of the ashpan.
Dave L and Steve drilled and tapped the top of the left-hand tank for the infill cladding.

Saturday 17th May.
Alex E, Bryn T, Kevin S, Peter M, Simon B, Steve M, Tony H.
This week should see a significant step forward with the restoration of the loco.
The boiler is planned to be taken out of the frames ready for its hydraulic and steam test.
In readiness for this we removed the two water tanks and placed them on a wagon that had been shunted alongside the loco earlier in the week.
We then removed the safety valve bonnet and the safety valve itself.
The crinoline that is nearest the firebox was removed along with the plate that the safety valve bonnet is attached to. This is to allow the chains  to lift the boiler. The few bolts that have been securing the smokebox to the saddle and the supporting bars were removed along with plates that allow the firebox to expand.
Lastly the firebars were  taken out and placed in the bunker.

Monday 19th May.
Bob L, Charles L, Dave L, Dave Mc, Peter M, Phil H, Steve T, Tony H.

Further work today on removing the steel pipes ready for hydraulic testing. The clack valves were taken to the machine shop for checking, they will then be hydraulically tested. Idea's were put forward on designs for the drop grate operating mechanism. 
Lots of cladding was painted in undercoat. 

Wednesday 21st 
Bob L, Dave L, Dave Mc, Peter M, Steve T, Tony H. 

Extra working day this week. The Loco was shunted into the Boiler shop and the Boiler was lifted off along with the ashpan. The ashpan was unbolted from the firebox and put to one side ready for further work to be done. The boiler will have the main steam pipe fitted, also the water trays. It will be filled with water, and any leaks dealt with. Then it will undergo a hydraulic test, then a steam test.
The two water tanks were refitted to the loco. All the cladding and the items that had to be removed for this operation were put away in the fruit D.

Thursday 22nd May
Today we were lucky to have 2 Network Rail employee’s on one of their volunteering days, working in the loco. They cleaned the inside motion and painted the inside of the frames where the firebox sits, chassis black. 

Tuesday 27th May. 
Jacob L, Peter D, Peter M, Phil H, Steve T, Tony H. 
As it was yet another Bank Holiday weekend, we decided not to work this Saturday and Monday. A few of us agreed to work today.
We split up into groups. One group drilled and tapped the final three holes for the infill cladding. In the boilershop more heat-resistant paint was applied to the boiler, also rivets and stays were reduced in length. The handbrake pedestal was bolted to the cab floor so a start can be made on installing the wooden cab floor.
We set up our trusty large mag drill that we had not used since we were at Bewdley, this was to check it over. We needed it to drill the 29mm holes in each tank for the bracing bar that runs across the back of the firebox. The mag drill did not let us down. Finally, the main steam pipe was moved to the boiler ready to be installed by the boilershop staff.

Saturday 31st May.
Kevin S, Peter M, Steve M, Tony H. 
Kevin swept up the swarf off the cab floor and also cleared the swarf off the top of the axle boxes.
Tony was working in the boilershop retrieving the last few boiler stays that had been drilled/burned out of the firebox. Using a couple of thin rods that were bent at the one end the rods were pushed through the mud hole apertures and hopefully when pulled back an old stay or part of a stay was retrieved. Kevin joined this operation and after a couple of hours all the old stays and some lumps of slag were removed from the water space in the bottom of the firebox, see photo.
After lunch we re-fitted the quadrant and the shroud in the cab ready for the wooden cab floor to be installed.