Sunday, 11 March 2018

Maintenance Update (ejector, injector, split, valve)

Last week’s conundrum
Several people (Gil, Andy B, John G, Stu F, Peter T) commented on the hole in the smokebox. The short answer is that it is for a large (4-cone) ejector.

The long answer is: 2807 has a Standard No.1 boiler and hence a standard smokebox to fit. This type of boiler is also used on certain passenger locos (Hall and Manor in particular). Passenger stock is vacuum fitted for braking, whereas in GWR days, most freight wagons were not. Passenger locos therefore had to create enough vacuum quickly enough to cause all the brakes to be pulled off on every coach. Freight trains probably only had brakes on the engine. This was no big deal, because they would rarely go above 30 mph. In the passenger loco cab, the small ejector (used just to maintain vacuum when stationary) was supplemented by a large ejector which could create vacuum much more rapidly. The steam used in creating the vacuum is exhausted into the smokebox via a pipe that runs alongside the boiler, below the handrail. Inside the Smokebox, the exhaust from the ejector is connected into the blower ring.

Two theories emerge: Our boiler (numbered 8270) had previously been used on Toddington Grange, Highnam Grange and Bostock Hall. Therefore, there would have been a large ejector and hence the hole would have been used for the ejector pipe (assuming the same smokebox was retained). Also, it is likely that Swindon would have made all smokeboxes for No.1 boilers with a hole, in anticipation of the boiler/smokebox being used on a passenger loco at some stage in its lifetime.

Tuesday 6th March
Mark Y spent time going round the plugs and mudhole doors, nipping them up for us.

Wednesday 7th
* Steam Feed to RH Injector leak (Collar joint)
The pipe from cab to injector is an awkward beggar to get out. Bruce and Nigel are in the cab with a huge spanner; Gil and John G are removing the nuts at the injector end.

The collar is towards the bottom of the pipe. Gil & John cleaned up the pipe but could see no sign of a leak. Gil is working out how to seal the pipe and make an adapter such that we can pressurise it (with air) and look for a leak. Gil found a drawing of the top nut from which to make an adapter.

John P finished his mechanical exam of our loco, and found a couple of missing split pins; a loose bolt, and a loose rivet on a die block.

Regarding the groan from the cylinder when 2807 was last shunted, by pushing the reverser into full forward, it opened up the exhaust steam port on the LHS valve, so it was possible to dribble oil down the port into the cylinder. Later, as 2807 was shunted up & down prior to going back into the shed, there was no further groaning … and rusty oil dripped out of the drain cocks!

* Back Safety Valve lifts at 220 psi
We decided to take no immediate action, as it is sensible to wait until she is properly in service before verifying the pressure at which a valve lifts. Experience has shown that it varies.

* Weld broken on smokebox door handle (inner handle for dart).
Someone removed the handle and took it away to be welded. Last seen in a queue awaiting its turn.

* LHS J-cock leaking.
Bruce tightened up the J-cock. He’ll monitor it when in service to see exactly where the steam is leaking from (or if he has fixed it).

I fixed the exploded tyre on the grotty trolley. Even this wasn’t easy - as I removed the wheel to
start work on it, several ball bearings made a run for it! Only found one.

Saturday 10th
Missing split pin from a spring was deemed a “red card”. A bar passes through the top of the spring connecting it to the axlebox (white arrow, right). The split pin passes through sideways to prevent the rod from rotating or dropping out.

It is a challenge to reach, and even more of a challenge to extract the bar. We could not simply push another split pin through - the bar had rotated! To release the bar, we had to jack up the loco frames sufficient that there was room to extract it; then jack up the spring to take the force off the bar. Believe it or not, doing this took Gil, Bruce, John T and me all morning! After lunch we then searched for a new split pin that was the right diameter and the right length. Bruce cut a slot in the end of the bar, parallel to the split pin hole, such that we can see it to line up the holes. Most of this task involved me laying on the ground between the frames; Bruce lying on the ground outside the frames; Gil kneeling down, and John trotting to & fro with tools!

Then came the news that we are needed on Tuesday as standby loco! The usual last-minute panic ensued. Valve covers needed fitting; running boards putting back; the injector pipe refitting …

Valves at 3pm

3.30 pm

4.45 pm

Gil, John and I attacked the valves: fitting the covers, then the “nose”, then the cladding. Followed by the running boards, inspection flaps and lamp irons.

Meanwhile, Gil abandoned me and John to help Bruce. John also helped them by making a joint (aka gasket) for the end of the injector pipe. It was decided to ignore the leak, as it was not that serious, so Bruce annealed a copper joint for the top end. As John and I departed after completing our work, Bruce and Gil were still desperately trying to persuade the injector pipe to go back where it came from. Since Gil took it out, he ought to know how to get it back … without taking the entire cab apart.

At 11.25 pm, Gil reported:
“The RH Injector steam supply pipe has been re-instated. It still requires testing to determine the extent of reported leakage. The brake valve exhaust pipe has been put back in place and the cylinder drain cock linkage re-connected.

It is recommended that a steam test be carried out to check the integrity of the newly made joints and check the condition of the injector steam pipe.”

For those of you who would like to see 2807 in action, she is rostered for:
(Train 3 on:) March 30 & 31; April 1, 2; then from 17 to 26 inclusive, 28, 29.


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