I made the original walthers scale kit on my layout. It could be made as either a rail or truck scale; I included both
George In Midcoast Maine, 'bout halfway up the Rockland branch
Seems to me that Conrail had at least one "weigh-in-motion" scale on one of their mainlines.
A quick search revealed this:
http://www.rrpicturearchives.net/showPicture.aspx?id=63742
Looks to me like it was set up for the engine to pull the entire train across the scale (at slow speeds, of course).
Something's wrong with the date on that pic, though. I got qualified on the River Line in 1985, and I don't remember that scale being there. Also, those look like SD60M's in the pic, and they weren't in production in 1982 (date as indicated in the pic). I'm thinking that it was taken several years later...
Soo 61245The weigh in motion version does not include a gantlet and prototype photos confirm this.
The older balance-beam scales had knife-edge bearing points.
PnLE_scale by Edmund, on Flickr
Modern scales use load cells that can withstand much greater impact. They are basically solid-state devices laminated in solid steel. The weight and impact of a locomotive would not affect them.
CN and others use these run-through inspection portals:
I don't know if they weigh, maybe not, but it would make a neat, contemporary detail on a modern layout.
https://www.traingeek.ca/wp/cn-rail-inspection-portals/
Cheers, Ed
Walthers did produce a scale track (scene) based on the earlier version of scales, with the gantlet track. The weigh in motion version does not include a gantlet and prototype photos confirm this.
An engine wouldn't be allowed to go on the actual weighing tracks, there'd be a separate track (sort of like a gantlet track) that the engine would use when pulling cars thru the scales. I believe that arrangement is how the Walthers kit is set up.
I will be installing this Walthers kit on my current era layout. First, I assume a locomotive moving over the scales would be permitted in the real world? The old scales would be layed out with a run-around to keep locomotives off the live rails when weighing cars.
The Walthers kit contains two separate weighing sections which can be spaced apart by the modeler. My question is, should these sections be spaced in such a way that a car of a certain length would have one truck on each of these sections at one time in order for the system to work? I'm thinking my scale might weigh gons of different lengths (52' or 65') or perhaps 100 ton aggregate hoppers which are much shorter.
I couldn't find an aswer to this question at sites that sell scales to railroads.
john