36 



cars on all ordinary bridges produce strains equivalent to 

 those of E 33. There are special cars which have, when 

 fully loaded, 50,000 pounds on each axle, but such cars would 

 never be put together in series. It is recommended that train 

 loading E 40 be the minium in adopted by any railroad in 

 North America carrying general traffic. Train load E 50, 

 under the requirements of these specifications, will, in the 

 opinion of the author, be sufficient to provide f or any possible 

 future loading. Many important systems have already 

 adopted it as their standard loading. 



THEODORE COOPER. 



