# FRA weight limit for high speed freight



## Joel N. Weber II (Sep 6, 2008)

The regulations describing FRA class 6, 7, 8, and 9 track state that if freight is operated at the speeds used for high speed passenger service, one of the requirements is that:



> (2) The load distribution and securement in the freight vehicle will notadversely affect the dynamic performance of the vehicle. The axle
> 
> loading pattern is uniform and does not exceed the passenger
> 
> ...


What defines the passenger locomotive axle loadings that are used, though? Is this limited somewhere else in the regulations?

I'm wondering what this really means in practice if we had any 200 MPH freight trains carrying USPS / UPS / Fedex packages and food that was all loaded into standard intermodal shipping containers. Would it need to be single stack for stability? Does using articulated car sets carrying the high speed freight to reduce the number of trucks needed work in this context? Could the shipping containers be loaded to the standard weight of a full standard shipping container as long as they're loaded evenly enough?


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## Guest_George Harris_* (Sep 6, 2008)

This paragraph is almost a "motherhood and apple pie" requirement. If it was decided to run freight on a line designed for high speed passenger service, the paragraph would be used to beat the railroad over the head to prove all these things were properly designed into the system. There are some vague points that could really become points of contention, such as:

Since any loading on an open vehicle such a a container carries will have aerodynamic effects, at what point do you define the affect as being "adverse"?

What is a unifrom axle loading? Is plus or minus 10% acceptable or does it have to be plus or minus 1.0%? Can you carry empty cars in a train or do they have to be loaded up to within the "acceptable" limit?

Passenger locomotive axle loading: I think the thought is that this will be the design load for the track. For example, the design load on some European systems is for a passenger engine axle load of 19 tonnes = 41,890 pounds, but what if your passenger service equipment is all electric multiple units having a design load of around 12.5 tonnes = 27,560 pounds? Does that become you freight axle load limit? Then, is it your design load for the track and structures or is it the axle load of the passenger equipment actually operated?

Way too much uncertainty in this regulation.

Double stack is unlikely because of its large cross sectional area and height. Also, for the articulated well cars, if you have any 20 foot containers involved, the loading on the intermediate axles approaches the current allowed freight limit of 286,000 pounds on four axles, that is 71,500 pounds per axle, which you really do not want to have at high speeds.


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