Ruth Ivimey-Cook (rivimey) post=423 wrote: Comparing the RM drawing and the photo below it there are several more differences...
- the leaf springs are wider in the drawing (on the photo they are only just wider than the wheels;
- only one coil spring in the drawing, vs two in the photo
- the photo has only a small foot/running board (LH side) while the drawing has a more continuous board.
- the cylinders at the extreme ends of the bogie are larger in the photo than the drawing.
Good spot Ruth. Looking again at the Mangapps bogie (now I wish I'd ducked lower to take this photo!) it looks like the single spring* bogies are the ones described as channel solebar:
I've put a * against single spring as looking at drawing SX22085 - the channel steel one, it looks like it has dual springs, but in the other orientation - towards the centre of the bogie rather than along the solebars.
I'm not sure you can read too much into footboards - it is well known that the LNER started economising on footboards from around the mid-1930s and the photo is likely to be then or afterwards. All the drawings I have of GE bogies have full length footboards.
The spring and rubber dampers probably varied depending on the usage of the coach - from what I can tell (and I'm struggling to actually prove) the channel steel bogies were primarily used on suburban stock with the others used on mainline stock - so larger springs and dampers for a smoother ride? Although the photo showing the channel steel bogie looks to not be a suburban coach due to the lack of doors...