Author

Timothy Watson

Date

13th April 2020

Reading Time

2 minutes

I haven’t been modelling, as such, but learning how to manage the A3. To do this I made up a rolling road from laser cut components so that all the subtleties of fire and water management can be achieved with the convenience of an engine running on the spot.

The engine prefers quite small coal and a deep fire.  Without a load on the rollers, the blower is needed to keep the fire lively.  All quite different to Frederick my traction engine!

https://youtu.be/7ufCsbSfSuc

The engine is lubricated by a displacement lubricator.  Many full sized engines used this (e.g. Valour).  A displacement lubricator works by having hot steam, piped from the boiler, condense on a reservoir of oil. This water then displaces some oil from the reservoir into a sight glass, as can be seen here.  The glass contains glycerine, so that the oil is imiscible and acts like a miniature 1970s lava lamp, floating up to the top. The rate of oil dispensed is controlled by the little valve at the bottom. The drop of oil carries over in a pipe from the top of the sight glass that feeds into the cylinder steam supply, therefore providing lubrication to the valves and pistons.

https://youtu.be/RxWzKrZWST4

Now I am content with running the engine, I will set to work on the cab.  This is about 1/8” too high and makes the cab area too ‘lofty’. The original GN and early LNER A1s had a high cab and boiler fittings (much as this cab), but the A3s had the group standard loading gauge, giving them a more powerful look.  Most of the height can be lost from the bottom of the cab, which is where the builder ‘grew it’ to accommodate the excess height of the original cab manifold, which has now been lowered.   Following this cab rebuild, the area will be repainted, as will the bogie wheels and new, correct, lining on the drivers.

Tim