Mountain wrote:Some listed as Dean goods had external frames and others had just the internal frames. Were they the same loco (See explanation below *) or a mistaken identification by those who publish modelling books? I know some get confused between Dean Goods and Collett Goods calling them all Dean Goods. The cab design being the give away!
* GWR used to use extra external frames when locos were made of iron as a safety feature as prior to this there was once a horrific accident when a locos axle broke at speed and a drive wheel came completely off. It was said that if an axle broke with the GWR external frames, the loco stayed on the track and the wheels were still contained in their usual position due to having two pairs of frames. Some other companies didnt bother adopting external frames. Later designs didnt need them once decent steels came on the scene.
Isn't the tender different too?
While tenders were generally remained the type fitted to the loco as new, at times there were quite some differences according to the locos depot requirements or according to what was available. Probably the best example of a weird missmatch on the GWR to keep trains in service was an ex Cambrian 4-4-0 which was paired up to the 8 wheel tender of "The Great Bear" which was the Great Westerns only 4-6-2 they made which was a huge loco in its day, hence why it didnt last long and was later rebuilt into a castle class 4-6-0.
The GWR didnt need 4-6-2's like thew LMS or the LNER did. The extra two wheels were to carry a larger ashpan for the long distance trips between London to Scotland. As the GWR had access to anthracite which burned without large deposits of ash, they didnt need to use large ashboxes on their longer distance routes so they could take advantage of the better power to weight ratio of using a 4-6-0 wheel configuration. Coupled to this, when the GWR introduced its castle class, for a while it was Britain's most powerful express locomotive. The general 0-6-0 locomotive with a tender were probably the most successful workhorse designs of all the companies. The Midland Railway which was absorbed into the LMS found them so useful that for years they would rather double head them (Or double head 4-4-0's) rather then use a single larger locomotive.
Due to the GWR's standardised parts locomotives like the Dean Goods and locos like some of the saddle and pannier tanks were almost identical apart from where they carried their coal and water. So standard were the parts used that under preservation a Prairie (2-6-2T) was rebuilt into a Grange loco if what I heard was correct.