Large Scale Central

AMS Rolling stock

“Those trucks I replaced with Accucraft ball-bearing wheel sets”

Phil’s Narrow Gauge offers a set of scale wheels and ball bearings that drop in without you needing to remove the trucks. You do have to unscrew the retaining strap on the bottom of the truck to drop the axleboxes and existing wheels, so you need a small Phillips screwdriver, and a steady handy to get the screws back in. (I use a Gripper from Micromark.) Oh, and don’t let the springs push the beam out or you’ll lhave springs falling on the floor.

“that’s when we all found out the nut for the bolster screw would break loose from the bottom of the car.”

Actually, the bolster screw is screwed into a tapped hole in a round brass tube which is held by a screw through the steel floor plate. (My tube = your nut.) If the top screw is loose, the whole thing just rotates if you try to remove the truck.

Some of us remove the steel floor, on the assumption it is overkill for a coach with heavy brass trucks. I usually replace it with an identical aluminum floor that holds the truck tubes/nuts in place. (My local True Value sells 1/16th alum in 12 x 24 sheets.)

"a guy built a flywheel car "

David Bailey of DJB engineering made one many years ago - I can find the photo if you want to see it. As Kevin says, it only provides inertia - which is fine for the first half of a downhill grade, but not so good on the last half when it is up to speed. Also makes it tough to stop the train when you get off the grade!

There was another ‘inertia car’ that would help - someone had one with a fan instead of a flywheel. The beauty of a fan is that its rotation is opposed by air movement, which is proportional to the sq of the speed. So, in practice, it has a well defined top speed above which it is difficult to spin - providing lots of drag.
Kevin - maybe a fan that can be engaged at the top of the hill and disengaged at the bottom will solve the problem?