The problem with the Gen-sets is one of ruggedness. Most RR equipment can be hit with a hammer and the hammer is the thing that gets damaged. The modular design is a great idea from a maintenance standpoint. What the modules are made up with is not quite up to the task. Another thing that works against them is the fact that they are essentially a Government mandate and as such the design was rushed and subsdised . The railroads have always been "If it works , don't fix it " and as such , new technology is accepted in a slow,reluctant,design as you go process. Most Gen-Set units sit because the crews and the mechanics either don't understand them or don't trust them. Having a locomotive fail on the job and cost you money has a tendancy to do that." Don't send me out there with that unreliable POS, Gimme the one that has worked without fail for years and let me do my job". Time is money and railroads are ALL about money .