Schools class question

Just seen a picture of a schools class crank axle, and there appears to be a sprocket with a chain on it to what did this attach?

 

It is tool being used to true up the journals, not a permanent fixture.

 

If it’s the photo on Facebook, it actually looks like the Q class crank axle, not the Schools! I think the same work was done to both though.

I happened to take these photos at the weekend of both crank axles. The Q has two cranks for the two inside cylinders and four eccentric sheaves for the two sets of Stephenson’s valve gear. The Schools has one crank and one eccentric sheave for one set of Walschaert’s gear.

Q class



Schools class.



Tom

 

It's what the key winds up.



Is that my taxi?

 

This one

 

Definitely the Q class, but the same work was done on both.

Tom

 

So what's the sprocket and chain for?

 

Does the Bluebell have its own kit for this or do they get contractors in?

 

Done by a specialist contractor. From the eNewsletter / motive power thread:

One such "heavy" item is attention to the crank axle of Q class No. 30541. Recently the loco has been "knocking" under steam, so immediately after our "Giants of Steam" event, No. 30541 entered the Loco Works for some attention and maintenance to the crank axle, big ends, small ends, eccentric straps, and axle boxes.

As I write, the crank axle has been removed and the journals are being machined, using a specialist company, to remove the 12 thousands of an inch taper across the length of the journal. Once complete, this work will ensure there is no twist under steam on the connecting rod putting pressure on the small ends.

[…]

Schools class No. 928 "Stowe" reached a significant milestone in October when the chassis was re-wheeled for the final time. The crank axle is yet to be installed as this also needs the same specialist machining, and once complete it will be fitted using our wheel drop. In the meantime, work continues on the chassis with the finer items while the inner firebox is stored awaiting fitting.

https://www.national-preservation.com/threads/bluebell-motive-power.33437/page-149#post-2299863​

Tom​

 

I hadn't seen that post