• DMUs

  • Discussion relating to commuter rail, light rail, and subway operations of the MBTA.
Discussion relating to commuter rail, light rail, and subway operations of the MBTA.

Moderators: sery2831, CRail

  by Trinnau
 
stevefol wrote: Mon Mar 01, 2021 2:32 pm I'm sure a solution could be engineered for the price electrification is going to need. But to some of the comments above about the weight of batteries, are folks here aware of the advances of Li-Ion in the last 10 years? The success of Tesla has led many railroads to look again at the battery concept, and in Germany in particular, dual mode Electric/EMU/battery is being seriously evaluated. It is depressing reading the old "FRA rules" stuff - rules that were designed over 70 years ago before silicon chips even existed, and are the thing that keeps so much passenger railroading third world in the US.
The FRA rules have more to do with crashworthiness especially in mixed use operation. Freight trains in North America are far larger than they are in Europe, so the standards in the US need to withstand higher potential impact thus need to be stronger. This results in more weight. As noted, the FRA has recently allowed for alternative concepts which allow some of the reduced weight.

My comment around weight and space is just that. An EMU without some kind of on-board power supply simply weighs less than "insert your carried mode of propulsion" - diesel/battery/hybrid/whatever. When comparing a battery locomotive to a diesel locomotive, battery technology just isn't there yet. It still has the weight and space drawback of a diesel engine. The only issue it solves is the noise/emissions, right now it is otherwise inferior in terms of actually delivering service regularly and will likely be for several years to come.
  by stevefol
 
I'm fully aware of *why* the FRA rules are the way they are, but it is a 1950's view to talk about "if a freight train crashes into a passenger train". Technology exists to make that a near impossibility. There's plenty more damage likely moving at the speeds of a European HSR. And the rules made little difference at Chatsworth CA when 25 people were killed - a totally avoidable and unlikely accident had there been anything that passed for up to date technology on the system.

It would make more sense for the FRA to allow operations like the MBTA to be exempt from those "big freight train" rules in much of their area. Aside from Willows-Wachusset and LJ to Haverhill, where on the system are passenger trains sharing tracks with freight trains with more than a dozen cars during the day?
Decent Regional service in Europe utilizes EMU's running at 100mph. Let the end of the Fitchburg and Haverill lines run with stupidly overweight cars and lumbering diesels, or insist that CSX/Pan Am runs its freights after hours.
  by eolesen
 
Technically, Amtrak is a 1950s view of how to run a train system. Should we get rid of that too?

Sent from my SM-G981U using Tapatalk

  by Trinnau
 
stevefol wrote: Tue Mar 02, 2021 6:23 pm I'm fully aware of *why* the FRA rules are the way they are, but it is a 1950's view to talk about "if a freight train crashes into a passenger train". Technology exists to make that a near impossibility. There's plenty more damage likely moving at the speeds of a European HSR. And the rules made little difference at Chatsworth CA when 25 people were killed - a totally avoidable and unlikely accident had there been anything that passed for up to date technology on the system.
A near-impossibility is not the same as an impossibility. System failures, multiple human failures, freight derailments that foul the main track but don't trigger the signal system or PTC, the list goes on. It's going to be a long time before that technology is virtually bulletproof.
stevefol wrote: It would make more sense for the FRA to allow operations like the MBTA to be exempt from those "big freight train" rules in much of their area. Aside from Willows-Wachusset and LJ to Haverhill, where on the system are passenger trains sharing tracks with freight trains with more than a dozen cars during the day?
Decent Regional service in Europe utilizes EMU's running at 100mph. Let the end of the Fitchburg and Haverhill lines run with stupidly overweight cars and lumbering diesels, or insist that CSX/Pan Am runs its freights after hours.
Right outside North Station, Worcester-Framingham, Walpole-Readville, Walpole-Foxboro (when that service ran) and occasionally Readville-Route 128. Part of the problem is that it could happen at any time though - a train could outlaw for some reason and not get to where they need to be after hours. And with the freight railroads required to provide common carrier service there is nothing preventing an industry from popping up and suddenly running big trains during the day. The dirty dirt out of Everett is a great example, daytime freight on the Lowell Line for a time, and if CSX restores Framingham to Everett B721 service that'll probably return to it's traditional slot in the early afternoon out of Framingham.

MBTA can "insist" on after hours operation but the way the freight railroads retained their rights in the sale of the lines it'll fall on deaf ears if it impeded the freight operation too severely. If the MBTA squeezes the freight operation too much the carriers will cry to the STB about interference in interstate commerce. The reality is about half of the MBTA lines see larger than 12 car freight trains at some point in a typical 24hr period.

I'm not downplaying EMU service, MBTA has set the direction to make that the next step. I just don't see DMUs as a reasonable step at this point in time. Maybe 5-6 years ago before the overhauls and bi-level purchase, but the fleet is going to be set for 10-15 years without a need for new vehicles. That will give them time to actually get done what needs to get done to move forward with Rail Vision/Regional Rail - provided they don't shelve the plans again.
  by BandA
 
Transportation is not risk-free; Why do we allow Prius and tractor-trailers together on dangerous, overcrowded highways? They should have automatic controls so that if automobiles try to tailgate a penalty-brake is applied.
  by rethcir
 
I think you will see EMU's on the Providence Line within a decade, if that is successful and commuting does begin to return to 2019 levels you will see political will to get the rest of the system electrified. Also if electric cars do become a majority of new cars sold (I see this taking at least 15 more years in this country) you will see more mandate for electric CR and effective CR in general.
  by BandA
 
Electric locomotives would make more sense on the Providence line, assuming a cooperative pooling relationship could be developed with Amtrak where Amtrak maintains the T's Providence Line locomotives and the T performs routine maintenance on the Downeaster.