Re: Rule 86 pertaining to weight capacity and truck journals questio

Tim Gilbert <tgilbert@...>

I wrote:

It would have saved
a lot of aggravation if nominal Capacity had been dropped in 1924 when
the powers that be at the ARA's Mechanical Division's Convention had
answered the CN's J. Coleman's query to the Chief of the Car
Construction Committee, the PRR's WF Kiesel Jr.:
Malcolm Laughlin wrote:

In 1967, I developed a new car type code for the NYC to standardize among sales, transportation and mechanical departments. That nominal capacity was an important part of the system for some car types. Hoppers were 50 ton or 70 ton. Most boxes were 50 ton. A large gon might be 70. New grain covered hoppers were 100 ton. The gross wt, light wt and load limits were consistent withinn a small range.

A 50 to car would have a gross weight of 140,000, a light weight of 40,000, or 39,100 or 39,700) and a load limit of 100,000 (or 101,000 or 103,000, etc.).

The Maximum Gross Weight a Car (or Gross Rail Load) could have on the rails for a car with 5 1/2" x 10" journals, the so-called fifty ton car, was allowed to carry 169,000 pounds up to 1962, and 177,000 afterwards. From this 177,000 pound Gross Rail Load (since your example is from 1967), the Light Weight of the car was deducted (say it was 45,000 for a 40' boxcar, or 55,000 for a 50' boxcars). The Load Limit would have been in 1967, 132,000 pounds for a 40' boxcar and 122,000 pounds for a 50' boxcar. (Before 1962, the Load Limits would have been 124,000 and 114,000 pounds respectively; the difference due to the 8,000 pound increase in the Gross Rail Load.)

The only restriction to what the Nominal Capacity was that it had to be equal or less than the Load Limit. Starting around 1930, the NYC consistently used a nominal capacity of 110,000 pounds for almost all its boxcars - an exception was the early Pacemaker cars in the #174000 series whose Capacities and Load Limits were 50,000 pounds - the NYC deliberately chose these amounts to protect their "high speed" trucks in 1946. They also did not stencil the Load Limit on them so they would be illegal to interchange which was the NYC's intention. If they wanted "legal cars," they could have placed a star next to the Load Limit stencil which meant that no one except the car owner could change the Load Limit.

For 70 ton cars I don't remember,
210,000 GRL pre-1962, 220,000 post-1962. ARA Design 2,748' cubic capacity Quad Hoppers weighed light about 53,400 pounds; hence the Load Limit was 156,600 pre-1962. B&A's 2,620' cubic capacity Trip Hopper #S-25249's Light Weight was 50,100 pounds; hence its load limit was 159,900 pounds pre-1962. After 1962, the Load Limits could have been 10,000 more. Meanwhile, a 2,000' cubic capacity Cement Covered Hopper had "70-ton" trucks, as did Ore Cars with about 1,000' cubic capacity, and Grain Hoppers with its roughly 3,000 cubic feet of capacity.

but for 100 ton cars it was 263,000, 200,000 (approx.) and 63,000, except for aluminum hoppers which were more like 210,000 and 53,000.
The pre-1962 GRL for cars with 6 1/2" x 12" journals was 251,000 pounds. The NYC had some four trucked depressed center flats which weighed light around 70,000 pounds. Their Load Limit would have been 181,000 pounds, and the Nominal Capacity selected was 180,000 pounds which was lower than the Load Limit.

The capacity could be part of a shipper's car order, and stencilled capacity was used in some tariffs as the basis for minimum loads.
For coal, this may have made some sense since a hopper loaded with coal would "cube out" about the same time as it "weighed out" although cubic capacity or load limit could have been specified instead of nominal capacity if notation of nominal capacity had been discontinued in the 1920's. I have been told that starting in the mid-1950's, shippers preferred fifty foot boxcars instead of forty footers except when loading high density bulk materials such as grain. Grain when loaded into a box car would generally "weigh out" before it "cubed out" - particularly if 3,000 cubic feet of grain could be loaded into a covered hopper having "70-ton" trucks. NYC's standard steel boxcars 8' 7" high inside had 2,955' cubic capacity, but rode on "50-ton" trucks (but whose nominal capacity was 110,000 pounds). For most commodities loaded into boxcars, the car would "cube-out" before it "weighed out." That's before consideration is given on how to load, unload, and restrain the load in transit, which could further reduce whatever weight the load was.

Please note that although my railroad experience was from 1959 on my comments are applicable to the steam era as not nothing had changed except for some larger cars.
I have to disagree with the tenor of this discussion.
I still maintain that using 40-tons, 50-tons, 70-tons as an adjective for the size of a car is not very descriptive particularly when you get into variations like NYC's 55-ton, or the New Haven's 60-ton ratings for its boxcars.

The Canadians somewhat solved the problem. If one looks at their nominal capacities of car series listed in the ORER's, the number of non-standard nominal capacities should be noted. The Canadians apparently selected nominal capacities which were much closer to the load limits than their American compatriots. Mr. Coleman's (of the CN) question at the 1924 ARA Mechanical Convention was answered in part by Canadian action.

It was the Americans who lost. Periodically throughout the late-1920's, 1930's, and particularly during WW II, there were RAILWAY AGE editorials imploring shippers to load up to the load limit to the extent possible in order to reduce car miles and possible car shortages. For instance, a PRR H21's Load Limit was about 80 tons - almost 15% more than their 70 ton nominal capacity.

Tim Gilbert

Join to automatically receive all group messages.