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  • 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

 #1564212  by BandA
 
One can add as many additional brushes and wheels as necessary to improve shunting. Incorporate instruments on board the DMU to test the shunt and sound the alarm to PTC & dispatch. Although I am sure the union contracts won't allow it, they could run a single DMU with a one-person crew, assuming automated proof-of-payment system, level boarding, and trainline doors. Why not? There is only one ?motorman? on long subway car sets, and no conductors ride on buses, silver line, subway or trolley.

Mentioned sand blocking the shunt. Then there is ice and leaves! Guess we'll need to order an automatic ice-scraper and a rotating whisk broom attachment for our new custom DMU!
 #1564214  by BandA
 
Biggest impediments to DMU's include that that they are expensive, custom-ordered equipment that is the same or more expensive than locomotives + coaches. It would be great if the MBTA had short sets or DMU's laying about for mid-day, weekend, and less-popular routes, but all the plentiful room that the railroads had has been sold off. RDC's were designed to save both labor cost and equipment cost, but modern FRA-certified DMUs are too expensive at this time. The fuel savings and particulate-emission reductions are not enough to make it worth it at this time.
 #1564221  by Red Wing
 
Problems can be overcome. The use of DMU's would be perfect as connector service like connecting Plymouth to the Kingston train, Connecting all the Old Colony Lines, Rockport and Newburyport. But the best use would be 2 car Fairmont line and stations within 128 providing that 15 minute service that the T wants.

The biggest issue I see with my suggestion is what to do with the extra engineers and conductors that aren't needed when you combine the trains.
 #1564237  by Trinnau
 
MBTA has clearly set direction for the next 15 or so years with their newer HSP46 fleet, rebuilds of the F40 fleet and procurement of bi-level coaches to replace the remaining aging single-levels. But the board has also clearly indicated a desire to move toward electrification and to explore MU-style service in certain corridors, and the existing fleet lifecycle will get them to a point of being ready to purchase new vehicles which will likely be EMU-type.

DMUs themselves just don't provide that much of a benefit over traditional commuter trains in the North American regulatory environment. They are too heavy to see a noticeable difference in acceleration, and the cost compared to overhauling existing equipment was just too much. The FRA has recently relaxed said requirements some, but too late for the MBTA's taste. A full DMU study was done by the Patrick administration in 2014 for the Fairmount Line and was even budgeted for procurement but was scrapped by the Baker administration in late 2015/early 2016, one of the main drivers being under-projected operating costs for what would be unique equipment on commuter rail.
 #1564259  by stevefol
 
The Stadler Rail FLIRT looks pretty much perfect for the MBTA. They could buy bi-mode, and initially start with a diesel powered generator in the center power unit, but in time switch to battery. Battery would be charged when running under the wires, meaning the MBTA could simply electrify short sections, terminii, and layover yards (where the overhead would be used to recharge the batteries). All the benefits of EMU without needing overhead wire everywhere.
 #1564303  by Trinnau
 
Batteries and engines all add weight to MUs, cutting acceleration, and take up space that could otherwise be given to seating, restrooms, ADA space, bike racks, etc. Not saying it's all or nothing, but a partial option is far less desirable, and doesn't provide you enough advantage over traditional commuter trains if you already have them and all of your infrastructure is designed around them.

MBTA put an RFI out last year for information on EMUs. The board presentation on the responses including some pros and cons can be found here.
 #1564509  by west point
 
It really seems to this poster that multi level EMUs are the way for MBTA to meet 2040 anticipated demand. There is a problem that I am un aware how it can be fixed. Is the bridge in Boston on the B &A route to Worcester still a low clearance restriction ? Can it be raised or replaced some way ?. Also does it impede the direct access to the Grand crossing track ?
 #1564510  by west point
 
It really seems to this poster that multi level EMUs are the way for MBTA to meet 2040 anticipated demand. The platform lengths at BOS south station does limit train lengths. There is a another problem that I never saw so am un aware how it can be fixed. Is the bridge in Boston on the B &A route to Worcester still a low clearance restriction ? Can it be raised or replaced some way ?. Also does it impede the direct access to the Grand crossing track ?
 #1564518  by nomis
 
If the multi-level EMU’s are the NJT MLV-3’s from Bombardier, they are shorter than the T’s current multilevel coaches. No need to worry about clearance envelope then.
 #1564520  by electricron
 
west point wrote: Sat Feb 27, 2021 9:56 pm It really seems to this poster that multi level EMUs are the way for MBTA to meet 2040 anticipated demand. The platform lengths at BOS south station does limit train lengths. There is a another problem that I never saw so am un aware how it can be fixed. Is the bridge in Boston on the B &A route to Worcester still a low clearance restriction ? Can it be raised or replaced some way ?. Also does it impede the direct access to the Grand crossing track ?
I'll admit I do not know, so the question I will ask in return is, does MBTA run double level Kawasaki or Hyundai Rotem coaches on this line?
Height of both the Kawasaki and Hyundai Rotem coaches are 15 feet 6 inches..
Height of a Stadler KISS emu train Caltrain is buying are 15 feet 10.5 inches.
http://www.tillier.net/stuff/caltrain/C ... 180705.pdf
That's just the height of the trains, not the catenary the EMUs need.
Depending upon the clearance requirements of particular sections of the route, the contact wire height would vary from about 17.6 feet to 23.5 feet.
https://www.caltrain.com/Assets/Peninsu ... ummary.pdf
Caltrain limits the lowest height of the catenary to 17.6 feet. Additional inches will be needed for electrical isolation from grounded structures - like a bridge.
What if the bridge clearance is taller than the Stadler car, but lower than the lowest catenary recommendations, the catenary could be eliminated and the train could run on battery or other alternate power for the length of the bridge.

p.s. It would really help this discussion if someone had the clearance height of the bridge in question and shared it.

Here's what I found to add,
https://www.mbta.com/news/2012-10-04/lt ... il-service
"The finalized CSX compact began with an initial closing in June of 2010, which set the entire project in motion, including the permitting processes and infrastructure work needed to allow for the relocation of CSX operations.
Today marked the second closing, completing the full transaction and allowing for:
Expanding commuter rail service to the Metrowest/Worcester areas by taking ownership and control of the rail line between Framingham and Worcester.
Raising the railroad bridge clearances from Westborough to the New York State line to allow, for the first time in state history, the double-stacking of full-size freight containers on trains serving Massachusetts."
I think we might be worrying about something already addressed.
 #1564538  by Trinnau
 
There are multiple bridges on the commuter rail network that would need adjusting to include wire clearance, including the B&A/Worcester Line. Typically this is actually done by undercutting and dropping the track as it is far easier and cheaper to do than raise the bridge. If the MBTA is going to commit to electrification this will need to happen at many locations.
 #1564569  by MBTA3247
 
Clearance-wise, there are no restrictions on any of the MBTA's equipment anywhere on the system. As mentioned, though, there are several bridges that would either need to be raised or the track lowered to provide clearance for catenary.

With regards to clearance improvements on the B&A, while one would hope they'd spend the minimal extra cash now to increase clearances to permit doublestacks + catenary, they may only provide clearance for doublestacks.
electricron wrote: What if the bridge clearance is taller than the Stadler car, but lower than the lowest catenary recommendations, the catenary could be eliminated and the train could run on battery or other alternate power for the length of the bridge.
For failsafe reasons, you don't want to do this when going under a bridge- if the pantograph doesn't get retracted, the moment it reaches the end of the catenary it will extend to full height and slam into the bridge.

The Mianus River Bridge on the Shore Line has a setup similar to what you've envisioned, but in that case trains are going over the bridge, not under it. The catenary on the approaches angles upward, allowing the pantographs to smoothly rise up and then be pushed down on either side of the movable span. There are several videos of this on Youtube.
 #1564612  by BandA
 
The bridges and the Prudential Center / Hynes Convention Center / Copley Place on the Ma$$achu$ett$ Turnpike Extension are not designed for catenary clearance. Undercutting would probably require redesigning the turnpike / railroad drainage system in several places. Alternatively, why not just add a battery to bridge any bridge gaps and run unpowered guide wires under the bridges. Although the B&A is no longer a clearance route CSX still has freight rights.
 #1564681  by stevefol
 
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.

Of course the real answer is regional rail, with a twin track North/South tunnel to permit cross-city running. There is so little freight in Eastern Mass it could easily be shifted to the nighttime, if trains bumping into each other, despite the available technology, remains a concern.
 #1564689  by BandA
 
The north-south rail link would cost about $10B+. Instead of spending $10B, just transfer to the Orange Line subway, or take an Uber. If you want to build useful infrastructure and must have a single-seat ride, upgrade the Grand Junction for a fraction of the cost. If you want to improve convenience get the Commuter Rail to use onto the Charlie Card 2, implement free transfers and implement equitable fares between CR, subway, and bus modes. Charlie Card 2 will probably cost $10B to implement...