Re: Car weighting


Bud, Tony, Bruce, and others,

when I started to model US prototypes more than 20 years ago I definitely wanted to run 100+ car trains with only one (larger) steam engine because this was reality for decades and is the main reason for my fascination of that era. Because of no available room and no ability to build an own layout I was restricted to "carpet or floor railroading". I purchased the only really useful track for this purpose (ROCO LINE) and choose not to use any unrealistically small curves - and the only one large enough from that company is 80" radius. The next smaller one is 35" which is already too small.
After building maybe 20 Proto 2k and Intermountain and Red Caboose kits and installing the weights per instructions and assembling these cars on a track for first trial runs I quickly thought "forget the 100 car train!"
Instantly I choose to remove all that dead weight and just add metal wheels (and Kadee couplers of course) to try how this would work - and it was very fine. I build about 120 more such kits - all without any additional weight - and frequently ran all of them in one train without any problems.
Then I wanted to "stretch the idea as far as I could" - I took the lightest car - Red Caboose 42' fishbelly side flat - re-equipped it with the original plastic wheel sets so it weighed only scary 15 grams and put it directly behind the engine. ZERO problems again. It also didn't make any difference to run some bad-rolling NMRA-weighted cars in between. One only had to be a little careful with acceleration and braking - which just adds to prototypical appearence...

Of course 80" curves are very large. Today - at the FREMO - I run half of that, and still have to try how those light weights will run there. Last year I have had a 64-car 100%-brass freight train running (mostly converted to Tahoe trucks) which went very well, too. Brass cars weigh in about 5 oz average, but the lightest one is a small frame-less tank car having only 63 grams. I had this one placed in the forward half of the train, but it really felt good, seemingly. No derailments.

As another member pointed out the NMRA rcommendations are from a time with VERY differently weighted cars and lots of bad-rolling trucks and smaller radius curves. Today I think those weights are much higher than necessary.
With the experiences mentioned above I would GUESS that steam era freight cars with free-rolling trucks (which have to be mounted properly and straight!) and metal wheel sets but without additional weight would safely run in long trains at 50" radius curves.

Sorry for the long posting.

Modeling the early post-war years up to about 1953

Gesendet: Samstag, 27. Juni 2020 um 03:17 Uhr
Von: "Tony Thompson" <tony@...>
Betreff: Re: [RealSTMFC] Car weighting

Bruce Metcalf wrote:

I use the NMRA weights in HO. I have also found that when there are problems, it's not the absolute weight, but combinations of light and heavy cars in one train. That, or putting light cars or just too many cars around too-tight curves.
There were studies in the model magazines back in the 1950s that concluded (possibly correctly) that the biggest factor in car weight performance was CONSISTENT car weight. As Bruce says, mixing heavier and lighter cars can bite you. I think one could very probably choose a weight below the NMRA weight now recommended, but the key would be, again, to STICK to that weight and get as close as you can with every car.
I continue to use the NMRA weight, but then again, I don't have any heavy grades that can hurt locomotive performance.

Tony Thompson

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