N&W 76950, Class H-15 Whopper Hopper

[NW Mailing List]

Somehow, folks got the idea this was a battleship gon, far from it. It was an experimental, one-of a-kind hopper, class H-15, No. 76950.

Dow had this to say about it in his chapter about experimental cars:

Another experimental car of 1963 did not last so long.  This was the class H15, road number 76950, which was a 150 ton car built in September 1963 to examine the possibility of using such large cars in unit-train service.  With a coupled length of 69’ 3” it was nearly half as long again as the H11 and H13 100 ton cars.  It rode on six-wheel trucks which used 61⁄2”x12” journals and roller bearings.  The ends of the trucks projected beyond the ends of the car and thus, unlike the HR and HV designs of over 40 years earlier, excessively long slope sheets were avoided.  Twelve pairs of discharge doors, much the same as those of the H13 car, were used, and in other details of design the H15 was very much an elongated version of the H13 design.  However the center sill was a 41.2 lb. Z section.  The sides were tied together with five tubular braces below the top side angles, and the slope sheets, again at 45°, ran up to the top end angles and dispensed with end sheets.

The H15 was extensively welded. The excessive use of welding in a coal car can lead to rigidity and an inability of the body to absorb vibration. No doubt the use of welding was to save weight and, possibly, to experiment with welding techniques.
Although the H15 was regarded as a 150 ton car its rated capacity was reduced from 300,000 lbs to 290,000 lbs in 1965.

The experiment did not last for long.  Although its later rating of 145 tons recognized its limitations, the H15 had a cubic capacity which, loaded with 54 lbs. per cu.ft. coal, would never carry more than 133 tons.  And, just as the H12 standard car had been judged by the harsh realities of operating economics, so was the H15.  Its light weight per ton of capacity, using the 133 ton figure just mentioned, was 761 lbs.  An equivalent calculation for the H11, already in service, was 713 lbs., and for the H11a, being designed in September 1963 when the H15 was being built, gave a figure of 608 lbs - considerably better The extensive use of cars of the size of the H15 would have required considerable alteration of facilities such as those at Lamberts Point, and this contributed to its demise.  Car 76950 was withdrawn from service in 1968.

Ken Miller

> On Nov 23, 2018, at 4:00 PM, NW Mailing List <nw-mailing-list at nwhs.org> wrote:
> 
> I move that  Mr. Hamilton, a lifer in the car side of the Mechanical Department, be required to submit a report on this car, including all dimensional and construction particulars, and a discussion of the physics behind operating such a car, as well as history of the car up to its disposition.
> 
> 
> 
> I do not recall ever seeing that thing.
> 
> 
> 
> -- abram burnett,
> 
> shop hand at the telegraph works
> 
> 
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