Monday 28 August 2023

Turn 150 - Firing the 7F

 It's Tuesday and it's a maroon service - two steam locos and a diesel, the Class 14. We are second off-shed after the BR Standard 4MT and I'm pleased that Third Man Henry has been in touch and will light up for us - I don't have to arrive until 07:30. It's not that I mind getting up early, but this turn is over 11 hours and if you start before your scheduled hours you will run out of time - you are only permitted to do 12 hours straight with 12 hours between shifts.

With Henry there, I was able to give the paintwork a good clean. The frames look like a job for later though:


It looked pretty good by the time we were ready to leave:

 
We took coal - a bucket half full of ovoids and half of fossil coal. The ovoids were on top, so I got to fire the first and second trips on ovoids, and Henry fired the 3rd and 4th on fossil - a lot of which was dusty.

There's no blow down valve on this loco; you treat hard water with tannin which keeps the solids in solution until you wash it out - which you do more frequently than on engines which you can blow down. These use soft water, which precipitates the solids out to the foundation ring so they can be blown out on a daily basis, which extends the washout cycle.

This loco is very sensitive to water levels, so I agreed with Driver Ed that we would aim at half to 3/4 glass throughout the day. Firing the first and second showed the engine wasn't too happy with the coal, my technique, or a bit of both - it wasn't maintaining pressure very well and we were arriving with it heading down to 140 - it redlines at 180; the water levels were spot on all day.




Having a look in the box, I realised that with a big back end in I was allowing the middle to get too thin, like the illustration from the Black Book - I've not fired this for a while and an unfamiliar loco takes a bit of getting used to; filling the hole in resolved the problem and I fixed it on the second trip.

It wasn't the magic bullet though. When people say 'big back end' and 'keep the front covered' that might work for fossil coal but on ovoids you need a lot more thickness - they don't shake down, any more than the coal in the tender moves forwards to avoid you double handling.

Next time I fire this I'll need to put a lot more in the front with more bed thickness; my back end was fine.

On the way back, I fired the front to keep the pressure up and let the back burn through - we had suspected it had clinkered and a few minutes with the bent dart proved that it had, though not badly. I cleared it out in Sheringham and laid a bit in the back end to save Henry a bit of time.


The third trip was a relaxing one for me - just a bit of hooking on & off. Henry, now through the ovoids and into the fossil coal had it just under 180 the whole way up with some smoke signals from the chimney. One of the features of using ovoids is that there is virtually no exhaust smoke, so you can't really tell when it has burned through.


Driver Ed was planning a little surprise for Henry. He'd been looking a little pale all day, mainly because he was covered in Factor 50 against the scorching Norfolk sunshine so it was perhaps less of a shock for Henry when Driver Ed claimed to be incapacitated at Kelling on the fourth up, and that he should take over. I sat back and watched as Henry took the train over Wind Pump and to a safe stop at Holt, with the miraculously-recovered Ed looking over his shoulder; all I needed to do was get a bit more water in the boiler. 

That's Henry another step closer to Passed Cleaner. 

I drove the fourth down, reminding myself how the Midland brake valve works and drove Light Engine back to shed. The stops were all good, including a yellow flag stop at Kelling; the Midlands style valve is easy to control using the vacuum, but personally I find the BR Standard combination brake valve easier to stop smoothly when you are Light Engine. 



Disposal went well; Henry was in charge under Ed's tutelage. 

I hope someone adds a chain to hold the upper ash pan door open though. 



Next turn? Same time next week, probably same loco. 

See you then. 

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