What would be the obstacles to making an operational weigh scale? I envision a scale platform mounted on the piston of a transducer and some form of digital manipulation to read out numbers in the range of a real weigh scale. Assured vertical movement with very little friction would be a must as would return to original position. Alternately inputting the car number could allow a PC to find where the car came from and if it was loaded or empty. The PC could then generate a fictitious car weight with none of the scale mechanical requirements. All that would be field required would be a number pad wth an enter button and a digital readout on the valence. any thoughts?
One of the mags had a how to build an operating one. I just went searching the MRMAG library search and can’t find it. Maybe someone here remembers.
(EDIT)
Found it. Check out the August 2000 MR. I’m pretty sure that is it. He a recalibrated guage and the scale actually depressed to give a reading on the guage electonically.
If not that one then April 1999 or Sept 2002.
If you are creating a ficticious weight, why bother with all the hardware, just indicate the car is being weighed and generate a number.
Dave H.
It would make sense if you measure the ounces. Then you can compare with the NMRA standards. And bad order the car if it has not the correct weight. 
But I guess for this use a common scale is more appropriate. And more simple!
Wolfgang
When reweighing the empty car periodically as required, be sure to redecal the car’s new empty weight amount, and date and location of the weighing.
[:-,] Mark
If you can’t raise the bridge, lower the river.
My locomotives have tonnage ratings, which I try to respect. To aid in my calculations:
- My car cards have light weight and capacity data copied from the prototype (by specific car number.)
- My waybills have a weight of lading for each loaded movement.
- Both of the above are in (metric) tons and tenths.
So if (fillintheblank) on train 507re is rated 350 tons Takami-Tomikawa, all I have to do is add up the light weights and lading weights. If the answer is more than 350 tons, there’ll be a pusher waiting at Haruyama when that train is scheduled to arrive. (Note that I am modeling a narrow gauge prototype with small locos, small cars - typically 15 ton capacity - and steep grades.)
IMHO, that’s a lot simpler (and less expensive) than fussing with sensors, LED displays and the intervening electronics - and it won’t die if dust gets into it.
Chuck (modeling Central Japan in September, 1964)
When I am a guest operator at someone else’s layout, it really “grinds” on me when the owner sets up trains that the locomotive or locomotives assigned have to slip and grind their way up grades. Talk about driver polishing and wear! If I had permission to back up and drop off some cars or double the hill, I would do so.
Mark
Stick this, or one like it, under your layout:
Cut out a slot in your layout for the scale, and build up from the platform of the scale so that the car actually weighs itself.
This one has a digital readout, costs $25, goes up to 35 pounds (in case you switch to G) and has a resolution of 1/10 ounce.
One could make the case that it the car has an out of standard weight it shouldn’t be on the layout in the first place.
Dave H.
Problem is if you try to assign prototypical weights to your cars and their lading you will get really bad results. In order to compensate for that you will have to start rounding down and substituting ficticiuos weights for things and you will end up about the same place as if you hadn’t bother with weights and went with a generic car count.
Model engines only have a maximum capacity to haul cars. So lets say one engine can physically move a maximum of 25 cars up your ruling grade.
Case 1. Lets say those are all loads and we’ll pick 1950’s era. Loaded cars in the 1950’s were commonly 50 ton capacity and weighed about 20 tons empty for a gross loaded weight of 70 tons. 25 cars x 70 tons is a tonnage rating of 1750 tons. So if you have a tonnage rating of 1750 tons then you can haul 25 loads up the hill. Great?
OK, an empty car weighs 20 tons. 1750 ton rating means the same engine can haul 87 empty cars up the same hill. Big problem, the model engine can only physically handle 25 cars, so that won’t work.
Case 2. Lets say those are all empties. 20 tons per car x 25 cars is a 500 ton rating. At a 500 ton rating, the engine can only handle 7 loaded cars by its tonnage rating. chances are you aren’t going to want that.
Case 3. You compromise on a rating halfway between the min and max. So 1750-500 is a 1250 ton swing, half of that (625) gives you a rating 1125 tons. A loaded train could be 16 cars. 16 x 70 tons = 1120 tons. An all empty train could be 56 cars. Still way over the physical limit of 25 cars.
Bottom
Funny - I’ve been doing this for years, and I’ve been getting really GOOD results. Of course, the weights are ALL fictional to start with - my cars are weighted to something close to the NMRA standard for HO, about 2.5 ounces.
That’s five more cars than will fit in my sidings, my staging tracks and/or the A/D track at the subdivision yard - not to mention, five more cars than my prototype handled over this stretch.
I reiterate (snipped from my original quote,) "I am modeling a narrow gauge