Joel N. Weber II
Engineer
There have been proposals for various improvements on the MBTA's Fairmount line, including the possibility of using Colorado Railcar's DMU, which is apparently the only DMU that meets North American heavy rail crashworthiness standards.
But, for example, here is a claim that the diesel engine Colorado Railcar has selected is somewhat underpowered.
If there's nothing already designed that would really quite work, why not consider an EMU for the Fairmount line as well? The satellite photos look to me like there isn't yet overhead power on the Fairmount line, but if most trains only run to Readville, that's not a huge distance to have to install overhead power on.
I'm also wondering if electric locomotives end up requiring less equipment than diesels that ends up taking up less space; you don't have the diesel engine and generator, but you presumably have to replace this with equipment to convert the power to the form the traction motors need. I assume that with a DMU, there's a desire to keep the space used by the diesel engine relatively small, which may limit the power they can produce.
But, for example, here is a claim that the diesel engine Colorado Railcar has selected is somewhat underpowered.
If there's nothing already designed that would really quite work, why not consider an EMU for the Fairmount line as well? The satellite photos look to me like there isn't yet overhead power on the Fairmount line, but if most trains only run to Readville, that's not a huge distance to have to install overhead power on.
I'm also wondering if electric locomotives end up requiring less equipment than diesels that ends up taking up less space; you don't have the diesel engine and generator, but you presumably have to replace this with equipment to convert the power to the form the traction motors need. I assume that with a DMU, there's a desire to keep the space used by the diesel engine relatively small, which may limit the power they can produce.