Atomic Systems

Are/were the trailing wheels (trailing bogie) fixed on the engine, or as is normally the case, able to move with the curve?

I'm curious because someone told me that they were fixed, and that is why the later models have the trailing wheels fixed, yet I've seen some earlier models where the trailing wheels are not fixed?

Flying Scotsman has a Cartazzi trailing truck. It looks like a conventional wheelset fixed in the frames however it is able to slide side to side. Also the horn guides it slides in are aligned at right angles to the center of the rear driving axle, this means that the axle moves in an arc to follow the curvature of the track. So basically the answer is both they are fixed to the mainframes and can move to follow the track.

You can just about make out the angled horn guides in this photo.
http://ratty.fotopic.net/p38217521.html
And a closeup with the wheels in place here.
http://ratty.fotopic.net/p39845683.html

Tim

Rfairlie wrote:It looks like a conventional wheelset fixed in the frames however it is able to slide side to side.

RFairlie, are you saying something similar that the trailing wheels can "steer" but within the fixed frame, similar to the Talgo trains (I think) & some trams? I think it's called radial something-a-rather?

Rfairlie wrote:Also the horn guides it slides in are aligned at right angles to the center of the rear driving axle

Sorry Rfairlie, I hate to say this, but I wouldn't really know what horn guides are?

So basically it is correct for a model of the Flying Scotsman to have either a fixed trailing wheel frame, or a trailer frame that moves (say for tight (un-prototypical) curves)?

PS: Oh by the way Rfairlie, thanks for confusing me even more!

Here are two views of the rear truck assembly...
http://ratty.fotopic.net/p39845692.html
http://ratty.fotopic.net/p39845693.html