njt/mnrrbuff wrote: ↑Mon Dec 23, 2019 10:02 pm
Yes, Downeaster trains don't need to be looped. Along the Downeaster route, many of the stops are pretty spread out, but there are spacings of less than five miles between Saco and Old Orchard Beach. It's six miles between Durham-UMH and Dover. Having DMUs run on the Downeaster will also enable extra seating capacity. The acceleration would hopefully be improved. Presently, the Downeaster Schedule is a big inconvenience, even with the 5th roundtrip. Plus, probably many of those trains can sell out too. Maybe by running DMUs on the Downeaster, there can be six or even seven car trains. I think that the Downeasters have five Amfleet 1s in the consist.
Let's add some practicability and talk efficiency into this discussion, amongst the last commuter rail operators running both DMU's and locomotive push/pull double level trailers was the TRE (Trinity Railway Express). The TRE chief operator expresses his opinion to the DART board years ago where the break even point was between the two type of trains. He answered 4 DMUs were about as efficient as 4 trailers and a locomotive - or vice versa. At less than 4 cars trains, DMUs were more efficient, with 4 cars or more locomotives pulling/pushing trailers were more efficient.
Nothing has changed this dynamic since. Modern day DMUs are not that much more efficient than old Budd built RDCs. F59PHI locomotives are about as efficient as newer diesel locomotives. So the formula should remain the same. For Downeaster trains running with 5 or 6 cars, the locomotive trailer type train should be more efficient and therefore cheaper to operate. For the Springfield shuttle with Amtrak running just two trailers with a locomotive in the consist, a DMU type train should be more efficient. Length of the train matters.
Now, I can find no facts to back up the TRE chief operator's opinions, but lets admit his opinion was based on actual operating experiences of both type of trains. I would also like to point out that all three commuter rail agencies in the DFW area; DART, DCTA, and TexRail; have limited the length of their DMU trains to 4 cars. So they actually believe what was written earlier.