Russ Elliott wrote:Am I right in thinking that the principle of the original Bachmann 1-B-1 sprung bogie is like this?
If so, the position of the point at which the body impinges onto the bogie is important, and will determine the track-holding of the axles. I think I would be inclined to sort the rear axle spring strength first, i.e. get the bogies running reliably without their front carrying ponies, and only then put enough strength on the pony spring sufficient for its track holding.
Justin's point about ensuring sufficient sideplay is also very pertinent.
In answer to Russ's qestion: Centerally over the two driven axels (Hence the bogies one the 40's and 44/45/46 pivot in an unprototypical position) attacked to the chassis at the top of the bogie tower.
The spring is for the pony wheels is almost neglegable straight out of the box. I normally remove the pony, give the strip of metal that acts as the spring a tweak, then add a strip of lead to the pony, and reattach ensuring the screw is not overly torked, to provide free play and allow gravity to take most of the work.
Also worth noting that you don't want the screw holding the bogie tower to the chassis overly tight, or your'll make the whole unit too tight and significatnly reduce road handling.
Regards
Matt