Hi Steve,
The railway is currently two miles between Middle engine lane (the museum end) and Percy main (with connection to the Metro). There was plans for an extension in the past, this even involved laying the ballast and drainage. Plus the new platform at California sidings. However this has been abandoned (not sure as to why).
TWAM are currently refurbishing the museum.
I was a volunteer at the time. When the extension was abandoned, it looked for a time as though the whole railway and museum might close.
The reasons were shrouded in secrecy, but the view I formed was that the extension project ran out of money and consumed a lot of the general budget too, without ever being close to finished.
I believe this was because things like the Swedish B class, another 060 tank engine and 5 mark 2 carriages weren't in the original costing. It did become a bit of a vanity project for some.
The B class needed overhaul, and turned out to have significant asbestos contamination. Eventually it was sent to Glasgow for decontamination. Upon return it was dumped in the headshunt and no progress made on overhaul.
The tank engine had been "overhauled" prior to delivery. It became apparent that this involved merely a 10 year boiler ticket being signed. There was no floor in the smokebox, so we had to put one in. The main steam pipes needed to be replaced because they were leaking. There was a big patch in the firebox which weeped from day 1. After several caulking attempts the loco was out of service within 2 or 3 years.
I'm was always a bit suspicious as to whether it was just mismanagement or whether there was a degree of fraud. At one time there had been grandiose plans for a northern extension.
Original plan was to terminate at Royal Quays, but Esso wouldn't sell the strip of land needed, which is why you can see a platform in the middle of wasteland on Google earth.
For many years there was no run round loop at the new Percy Main station, so trains were top and tailed.
