Seaport District to Back Bay DMU Plan

Irish Rail 22000 class DMUs have MTU engines mounted on rafts and swapped in and out. Is this the kind of thing you mean here, papabarn?
http://www.irrs.ie/Journal%20170/170%20 ... 0Class.htm" onclick="window.open(this.href);return false;

Powerplant and drive train was chosen from MTU of Germany, a subsidiary of Mercedes Benz. MTU is a very well regarded rail engine supplier. The engine fully meets the demanding EU emissions directive Class 3a and is the most advanced currently available in terms of emissions. The MTU under-floor “raft” combines the engine (rated at 360kW), Voith hydrodynamic transmission, 3-phase auxiliary power generation, cooling systems, fire protection, hydraulic systems and exhaust silencer all located in a suspended ”H” frame which allows for easy removal. An identical raft is fitted under every vehicle and operates independently. There is a certain amount of power sharing between vehicles in degraded operation and it is an area being looked at currently for further improvement.

dowlingm wrote:Irish Rail 22000 class DMUs have MTU engines mounted on rafts and swapped in and out. Is this the kind of thing you mean here, papabarn?
http://www.irrs.ie/Journal%20170/170%20 ... 0Class.htm" onclick="window.open(this.href);return false;

Powerplant and drive train was chosen from MTU of Germany, a subsidiary of Mercedes Benz. MTU is a very well regarded rail engine supplier. The engine fully meets the demanding EU emissions directive Class 3a and is the most advanced currently available in terms of emissions. The MTU under-floor “raft” combines the engine (rated at 360kW), Voith hydrodynamic transmission, 3-phase auxiliary power generation, cooling systems, fire protection, hydraulic systems and exhaust silencer all located in a suspended ”H” frame which allows for easy removal. An identical raft is fitted under every vehicle and operates independently. There is a certain amount of power sharing between vehicles in degraded operation and it is an area being looked at currently for further improvement.

Seems quite similar although I envision more than one "H frame" allowing for more than one "raft" so that power could be increased if desired for pulling additional unpowered coaches and providing sufficient "HEP" for them but yeah.. Also, I envision both trucks (bogies) to be powered possibly using traction motors rather than a "transmission". One thought behind the traction motors maybe being the ability to make the unit "dual power" (third rail or by adding a pantograph?).. Nice find!

Given the size of a powerpack that will likely be required to move an FRA-compliant DMU, I'm not sure how many you'd actually be able to fit under a single railcar, especially if we're including a generator.

The option that makes much, much more sense is to set up your DMU as a DEMU, with electric motors in the bogies and your diesels serving as gensets, which could then potentially be started and stopped selectively depending on power demand or anticipated needs if you really wanted to be fancy, though I don't know if anyone has taken that concept as far as using the motors as gensets yet.

The DEMU on the other hand is an extremely well-proven concept, both for short-spacing, "stop and start" services and (with advance apologies to F-line) especially over long-distance services. Google the British Rail class 220/221/222, which at this point have been in service for over a decade with minimal headaches. Dual-modes D/EMU's are the next frontier, and while they pose a real technological challenge, the powers that be in Europe must be quite confident that they'll work, because the UK is hanging all of it's high-speed mainline service on the new Hitachi Class 800 high-speed diesel-electric dual-mode multiple units, and SNCF has decided to hinge its regional and suburban services on its new Alstom Regiolis Bi-mode D/EMU's.

It's doable, but it remains to be see whether a North American railroad will have the vision to dig its operations out of the relative stone age (tell me with a straight face that the MBTA's current operations are any different than Southern Pacific's Eisenhower-era Bay Area service, instead of FM Train Masters and Pullman Galleries, we have HSP46's and multilevels, what an improvement!) and embrace some real 21st-century transit solutions.

papabarn wrote: although I envision more than one "H frame" allowing for more than one "raft" so that power could be increased if desired for pulling additional unpowered coaches and providing sufficient "HEP" for them but yeah.. Also, I envision both trucks (bogies) to be powered possibly using traction motors rather than a "transmission".

Bramdeisroberts wrote: The option that makes much, much more sense is to set up your DMU as a DEMU, with electric motors in the bogies and your diesels serving as gensets, which could then potentially be started and stopped selectively depending on power demand or anticipated needs if you really wanted to be fancy, though I don't know if anyone has taken that concept as far as using the motors as gensets yet.

I think we're saying the same thing using different words, what with traction motors being electric motors.

Bramdeisroberts wrote:The DEMU on the other hand is an extremely well-proven concept, both for short-spacing, "stop and start" services and (with advance apologies to F-line) especially over long-distance services. Google the British Rail class 220/221/222, which at this point have been in service for over a decade with minimal headaches. Dual-modes D/EMU's are the next frontier, and while they pose a real technological challenge, the powers that be in Europe must be quite confident that they'll work, because the UK is hanging all of it's high-speed mainline service on the new Hitachi Class 800 high-speed diesel-electric dual-mode multiple units, and SNCF has decided to hinge its regional and suburban services on its new Alstom Regiolis Bi-mode D/EMU's.

Thanks for the tip! I'll check it out this evening.

Bramdeisroberts wrote:It's doable, but it remains to be see whether a North American railroad will have the vision to dig its operations out of the relative stone age (tell me with a straight face that the MBTA's current operations are any different than Southern Pacific's Eisenhower-era Bay Area service, instead of FM Train Masters and Pullman Galleries, we have HSP46's and multilevels, what an improvement!) and embrace some real 21st-century transit solutions.

No argument from me there!

UPDATED 27 Oct 2014 1952 EDT.
Just took a quick look at some of the material on-line about the three classes. Nice! That said however, part of what I envision (and the need for additional power capability) is that the unit be able to "mate" with other, unpowered CR rolling stock of various manufacture such as what the has now and pull one to maybe two or three coaches as "trailers" (maintaining track speed). Not a dedicated "set" of cars.

The MTU powerpack shifts a 22000 consist at 100mph service speed on InterCity runs with its 483bhp 6H1800s. The Nippon Sharyo DMUs have QSK19-Rs at 760hp to move at 90mph. So I guess there is a bit of a weight difference, among other differences.

EDIT: Bostonians following the entry to service of the Rotem cars might be interested/amused to know that two three car 22000 class DMU consists had to be scrapped, because in transit from Rotem they were shipped on the same freighter as a load of fertiliser, the fumes from which wrecked the electronics of the cars to the point that they were written off and replaced at the end of the order (I believe the shells may have been reused)

papabarn wrote:UPDATED 27 Oct 2014 1952 EDT.
Just took a quick look at some of the material on-line about the three classes. Nice! That said however, part of what I envision (and the need for additional power capability) is that the unit be able to "mate" with other, unpowered CR rolling stock of various manufacture such as what the has now and pull one to maybe two or three coaches as "trailers" (maintaining track speed). Not a dedicated "set" of cars.

That can't be done. It's not an MU if every car including the dead trailers doesn't have MU electronics. The only way to move off-shelf coaches with run-of-the-mill 'dumb' HEP hookups is to do power cars. Sort of like a low-speed, modular Acela trainset that can be strung together like tinker toys with power cars at the ends and in the middle. It looks superficially like a DMU/EMU because you have distributed power scattered through the consist, an acceleration advantage that for all intensive purposes is within a rounding error of a real DMU/EMU, and seating and passenger pass-thru in the power cars. But because of the lack of MU'ing electronics the cars in the consist are not talking to each other at more than a very basic passive level, so the power cars end up acting as much-minaturized push-pull locomotives...same general principle as a double-draft consist like the Cape Flyer or some extra-long Amtrak LD with multiple locos. The power cars, while having miniaturized engines, still have to overcorrect for a dead mass of unknown properties...meaning bigger engines that lose most of the efficiency advantage of a real DMU. And a whole ton of seats because the power car engines and fuel tanks are a lot bigger than a standard DMU's. You'd probably have to do those as bi-levels to make the seating capacity at all useful in a consist. All because they're not DMU's at all despite the superficial resemblances.

It's only when you get real MU'ing that the entire consist--unpowered trailers and all--is in perfect bi-directional communication and can distribute the power so finely-tuned that the entire consist acts like one unified self-powered car. Thus allowing you to shrink the engines further, pack more seating, have smooth and self-correcting acceleration, and achieve much greater energy efficiency. As long as you've got 'firewalled' lash-ups with off-shelf coaches and a simple passive HEP hookup...the power cars have to be some degree of overkill. Much less so than a push-pull loco, but operating on the same brute-force principle. That's the essential difference between MU'ing and not-MU'ing, and the reason why every DMU (right back to the original-configuration Budds) and every LIRR/MNRR M-series EMU can only trainline with dead trailers that are exact unpowered copies of itself equipped with MU--not HEP--hookups. You wouldn't be able to trainline an M2 bar car on a push-pull set just like you'd never be able to trainline any MBTA coach sandwiched between DMU's. Much like new subway cars have to be custom-ordered to MU properly with another similar class of subway cars...there's no standard generic enough to cover all known (or unknown) variations, so very large systems like NYC and Chicago have a lot of overhead on designing their MU specs every time they churn through another new order.


Now...is there a practical way around this? I don't know. I suppose you could could produce or overhaul a set of coaches that have both--and separate--HEP hookups and MU hookups. One set of wiring plugs into a push-pull set, one set of wiring plugs into an MU set. But the MU trainlining is so make-and-model specific that it's virtually impossible to future-proof them around a standard that plugs into any make of DMU. Therefore those coach mods would only be able to work with one DMU make only; a next-gen DMU purchase, unless ordered to be more or less a copy of the first-gen (with whatever evolutionary limitations that puts on the second gen), would be off-limits to those rewired coaches. Making coaches extremely hard to maintain over their lifespans as 'universal' cars. The economics of such a dual-mode conversion probably don't even come close to washing given how evolutionarily different the second- and third-generation FRA-compliant DMU's are likely to be from this first generation.

Believe me...the UK and Europe have been trying for ages to lick this compatibility problem. Subway systems in the U.S. have been trying for ages to lick this very same compatibility problem. It is most definitely not for lack of effort and vision. It really is that difficult a technical problem to design an MU system for the 'every-car'. The closest it's come to being practical are classes of unlike-make British DMU makes that can trainline with each other in all-DMU sets by stripping their MU hookups into layers--one a baseline standard, one a model-specific layer. Those lash-ups come with speed restrictions in-practice, and much more herky-jerky starts/stops that aren't terribly comfortable for passengers. They tend to avoid trainlining unlike makes together in this way because of those performance limitations and isolating those kinds of consists to select routes where 2 outer branchlines from different operating divisions--each with its own equipment pool--converge and lash up at a mainline station for the remaining distance to a large destination. It's a limited at best solution in countries that do have extremely large DMU/EMU installations. For a small introductory installation like the T's and a hub system where every route goes one-seat to the terminal, the scale doesn't come close to make it worthwhile for them to take a stab at this same problem.



NJT was briefly considering power cars for its Arrow EMU replacements, with Bombardier making single-ended power cars inside an MLV coach shell that could sandwich 2 off-shelf MLV coaches (i.e. a 4-car train is 2 power cars on the ends, 2 coaches in the middle...a 7-car train is 2 power cars at the end, 1 power car in the middle, 4 coaches split 2 on each side of the middle power car). Full upper level's worth of seating, maybe two-thirds a typical lower level's seating before the electrical transformers claimed the rest. NJT wasn't sold on the implementation. Too many seats lost in the lower level of the power cars, technology not mature enough to be sure it would really work with all instead of some of their coaches. And that was on an electric-only vehicle that doesn't have to fit fuel tanks; a diesel power car of similar design would be a lot harder and probably cannibalize most of not all of the lower level. NJT ended up in the fleet plan they released last month opting for fully traditional EMU's in the MLV form factor. It's entirely possible if it's a Bombardier product that it'll literally be in the same exact carbody as a MLV coach. It's entirely possible that they'll offer for sale dead trailer versions for that EMU make that are literally an MLV coach with MU electronics. But despite the similarities it'll never be possible to lash up a real MLV coach in one of those lookalike EMU consists. Because one communicates with continuous, 'talky' MU electronics...and one is passive.

The cool thing about DMU/EMU/RDC is the power guts are all below the floorboards. If you can cram enough horsepower into a replaceable modules to also power a trailer, that would be great! If you need to remove seats, thats diminishing returns.

The DMU cars could talk to each other, detect 1 or more random trailers. After accelerating for a few minutes the weight of the load could be calculated. Or model nos. could be entered into the on-board computer at lash-up time. Or add digital radios to each coach that transmit every 30 seconds over the power cables "I am a MBB model X MBTA#1234 weight=4567lbs rolling friction=Y".

DMUs need to be cheaper than buying locomotives + trailers. Otherwise there is no point.

BandA wrote:The cool thing about DMU/EMU/RDC is the power guts are all below the floorboards. If you can cram enough horsepower into a replaceable modules to also power a trailer, that would be great! If you need to remove seats, thats diminishing returns.

The DMU cars could talk to each other, detect 1 or more random trailers. After accelerating for a few minutes the weight of the load could be calculated. Or model nos. could be entered into the on-board computer at lash-up time. Or add digital radios to each coach that transmit every 30 seconds over the power cables "I am a MBB model X MBTA#1234 weight=4567lbs rolling friction=Y".

DMUs need to be cheaper than buying locomotives + trailers. Otherwise there is no point.

Yeah!

BandA wrote:The cool thing about DMU/EMU/RDC is the power guts are all below the floorboards. If you can cram enough horsepower into a replaceable modules to also power a trailer, that would be great! If you need to remove seats, thats diminishing returns.

The DMU cars could talk to each other, detect 1 or more random trailers. After accelerating for a few minutes the weight of the load could be calculated. Or model nos. could be entered into the on-board computer at lash-up time. Or add digital radios to each coach that transmit every 30 seconds over the power cables "I am a MBB model X MBTA#1234 weight=4567lbs rolling friction=Y".

DMUs need to be cheaper than buying locomotives + trailers. Otherwise there is no point.

Unfortunately that detection of multiple trailer types is exactly the technical hurdle that no one in the world has licked on any DMU/EMU to the point where any production product can do it with the type of glitch-free efficiency to make it a viable purchase option. Passive HEP+cab hookups are just too different from active MU hookups to couple with non- MU-specific dead trailers, and it would take Frankenstein mods to turn a coach into something capable of trainlining with an MU (and probably only one make of MU...possibly at sacrifice of ability to switch between MU's and push-pull sets). See my previous post on the essential differences between MU trainsets and push-pull + power car (incl. power cars that ape some of the characteristics of MU's) trainsets. The differences are too fundamental to count on some 'great leap' in technology to be right around the corner.

And MU hookups are so model-specific that no universal standard has yet been developed. Subway cars that trainline with unlike makes usually are designed as workalikes or with translation layers for X, Y, Z similar-ish makes...and not A, B, C more dissimilar makes. Remember how lousy those first 2 pilot Type 7 conversions rode when trainlining with the Bredas...it took years of tweaking to square the difference in the 7s' DC motors vs. the 8s' AC motors enough that riders wouldn't notice the difference and they could proceed with converting the rest of the Kinkis. And 8-8 and 7-7 sets to this day still ride a little smoother than mixed sets. It's like that right through heavy rail cars, EMU's (the Silverliners are the only ones in North America right now that can trainline with multiple generations of itself...DC and AC motors), and DMU's (such as the UK Network Rail makes that they keep segregated except when unavoidable because of the performance penalty).

So the T does have to consider that. These first 30 DMU's may have to be segregated from the next order if the next order is a make that's not an exact copy of the first. Which requires a lot more careful planning on long-term fleet acquisitions because of all the variables in equipment scale and cost of scaling up the fleet. It's eminently manageable, but you can easily see why there's hesitation to jump in head-first. Buy a starter fleet as first move and you sort of have to have it well- gamed-out what your second move with that vehicle type is likely to be.



Another thing you do have to consider is that a lot of DMU's are diesel-mechanical instead of diesel-electric. Self-propulsion with an internal combustion engine is still a lot easier to pull off with considerably older-school direct-drive transmissions instead of conventional traction motors like all push-pull locos and EMU's, albeit a lot more modern than archaic first-gen diesel locos that used that technology. Ottawa O-train's Bombardier Talent VT 643's, Sprinter's Siemens Desiro's, and the Nippon Sharyo vehicles for SMART and Union Pearson Express, and the now-obsolete Colorado Railcar DMU's are all diesel-mechanical. Whereas the ubiquitous non- FRA-compliant Stadler GTW's used in virtually all time-separated DMU operations in this country are diesel-electric. Most DMU families do offer diesel-mechanical and diesel-electric variants, so I'm not sure why the purchases in this country skew so heavily to diesel-mechanical . Maybe something to do with the weight when it's carrying that extra FRA compliance bulk? Can't find any info online describing why those technologically have the sales advantage.

At any rate, the maintenance practices are a lot different with those than the traction power universal to all of the T's commuter rail power, and I'm not sure how that plays into maint cost, training for the shop techs, and what the maint facilities need to be equipped with. Under the hood it's a lot more like maintaining a bus than a locomotive. And I don't know how in the hell Union Pearson plans to convert its DMU's into EMU's after GO Transit starts electrifying its network. It's definitely doable with AC traction because all kinds of locomotive families (Siemens Sprinter vs. Charger and ALP-46 vs. ALP-45DP, for instance) have a lot of component commonality differing just by power source and power source-specific design elements. But it seems like it would be an incredibly unconventional or unwieldy job for UPE/Metrolinx to convert one of those diesel-mechanical things into an EMU at cost and reliability less than just outright replacing them with EMU's. While in theory such a conversion should be pretty straightforward to convert a properly modular diesel-electric DMU to an EMU if the 'family' lineup of a particular make offered such a transitional model.

So that's another set of considerations consideration where the long-term vehicle strategy has to be very carefully thought-out before taking the plunge. Maintainability, fundamental differences from the rest of the fleet in propulsion tech, scalability of the fleet...whether the more numerous FRA-compliant diesel-mechanicals are a long-term bet or if it's better to wait, see, and comparison-test a wider selection of diesel-electrics if/when they become more available as FRA-compliants. And so on.


Look sharp, engage brain, have a very fleshed-out mission statement on how they'll be used, think long-term and multiple purchases down the line, exercise proper caution, eliminate all ambiguity before purchase, etc., etc., etc. You get the picture...it's a VERY rigorous evaluation process, much moreso than procurements for a conventional fleet. We want the T to take its time--take all the time it needs--before making the purchase from the results of this RFP. And to absolutely not feel pressure to rush it if it in any way compromises their ability to nail down all those considerations spot-on. Not for the faint at heart.

F-line to Dudley via Park wrote:Under the hood it's a lot more like maintaining a bus than a locomotive. And I don't know how in the hell Union Pearson plans to convert its DMU's into EMU's after GO Transit starts electrifying its network. It's definitely doable with AC traction because all kinds of locomotive families (Siemens Sprinter vs. Charger and ALP-46 vs. ALP-45DP, for instance) have a lot of component commonality differing just by power source and power source-specific design elements. But it seems like it would be an incredibly unconventional or unwieldy job for UPE/Metrolinx to convert one of those diesel-mechanical things into an EMU at cost and reliability less than just outright replacing them with EMU's. While in theory such a conversion should be pretty straightforward to convert a properly modular diesel-electric DMU to an EMU if the 'family' lineup of a particular make offered such a transitional model.

That's the question that I have about Canada's plans with their N-S units as well. It'd be one thing if they were DEMU's like the Virgin Voyagers and electrifying them was as simple as ripping out the diesels, replacing them with transformers, and bolting a pantograph on the roof. On the other hand, the N-S units seem by all means to be your standard "diesel with a Voith transmission driving the bogies with a cardan shaft" type of units, but could it be possible that N-S dreamed up something crazy like body-mounted traction motors driving the bogies through those same shafts?

That's not THAT uncommon of a setup for EMU's, though IIRC it's much more common on high-speed trainsets where minimizing unsprung weight is the top priority (though you could say that N-S is, ahem, pretty well known for their lightweight high-speed EMU's...)

In today's day and age, I don't think plopping an electric motor where an internal combustion engine used to be is a huge ordeal. Almost every automaker is doing this now (VW, Ford, Chevy, Nissan to name a few..) - offering the same model with ICE, electric, diesel, hybrid, etc..

Bramdeisroberts wrote:

F-line to Dudley via Park wrote:Under the hood it's a lot more like maintaining a bus than a locomotive. And I don't know how in the hell Union Pearson plans to convert its DMU's into EMU's after GO Transit starts electrifying its network. It's definitely doable with AC traction because all kinds of locomotive families (Siemens Sprinter vs. Charger and ALP-46 vs. ALP-45DP, for instance) have a lot of component commonality differing just by power source and power source-specific design elements. But it seems like it would be an incredibly unconventional or unwieldy job for UPE/Metrolinx to convert one of those diesel-mechanical things into an EMU at cost and reliability less than just outright replacing them with EMU's. While in theory such a conversion should be pretty straightforward to convert a properly modular diesel-electric DMU to an EMU if the 'family' lineup of a particular make offered such a transitional model.

That's the question that I have about Canada's plans with their N-S units as well. It'd be one thing if they were DEMU's like the Virgin Voyagers and electrifying them was as simple as ripping out the diesels, replacing them with transformers, and bolting a pantograph on the roof. On the other hand, the N-S units seem by all means to be your standard "diesel with a Voith transmission driving the bogies with a cardan shaft" type of units, but could it be possible that N-S dreamed up something crazy like body-mounted traction motors driving the bogies through those same shafts?

That's not THAT uncommon of a setup for EMU's, though IIRC it's much more common on high-speed trainsets where minimizing unsprung weight is the top priority (though you could say that N-S is, ahem, pretty well known for their lightweight high-speed EMU's...)

I don't think it's a matter of "could you do it". Metrolinx probably has thought that out. It's more "is this the least bit cost-effective"? I have the feeling when the GO Transit wires go up that UPE is just going to end up buying new EMU's and re-selling its DMU fleet to another Canadian city with light miles on the odometer. If the unit cost of changing a diesel-mechanical DMU over to an electric traction EMU--or some electric-mechanical FrankenEMU--ends up higher than just tagging along with GO's first big EMU order and customizing a few units with extra luggage racks...seriously, why bother. Go the least path of resistance.


But UPE was widely criticized from Day 1 for being a patronage cesspool for a bunch of politicos to enrich themselves, and has spared no cost overrun in the process. So they clearly weren't thinking 10 years from now...that's the next guy's problem. It'll be a good service in the end...and a better one under wires whether it's with converts of these existing cars or a reboot with new GO stock. But the chefs stirring the pot didn't exactly coat themselves in glory with their planning acumen. The people-related cleanup on that project was long ago written off as sunk cost.

Could it be possible that N-S designed their DMU with "plug and play" conversion to electric power in mind? I only say this because while the Japanese manufacturers don't seem to lump their designs into "families" the way Alstom/Siemens/Bombardier do, one look at the absurd number of different DMU and EMU designs rumbling across Japan (seriously, browse the Japanese wikipedia and you'll see that they seem to have more classes than the UK, France, and Germany combined) and it's clear that there's likely a ton of shared DNA among the three different loading/track gauge combinations over there, because if there wasn't, then Kawasaki/Hitatchi/Fuji Heavy Industries/Mitsubishi/Nippon-Sharyo/Kinki-Sharyo/Tokyu Car Company would have all gone bankrupt years ago.

Nippon-Sharyo even builds EMU's here already, for the electrified Chicago service.

Bramdeisroberts wrote:Could it be possible that N-S designed their DMU with "plug and play" conversion to electric power in mind? I only say this because while the Japanese manufacturers don't seem to lump their designs into "families" the way Alstom/Siemens/Bombardier do, one look at the absurd number of different DMU and EMU designs rumbling across Japan (seriously, browse the Japanese wikipedia and you'll see that they seem to have more classes than the UK, France, and Germany combined) and it's clear that there's likely a ton of shared DNA among the three different loading/track gauge combinations over there, because if there wasn't, then Kawasaki/Hitatchi/Fuji Heavy Industries/Mitsubishi/Nippon-Sharyo/Kinki-Sharyo/Tokyu Car Company would have all gone bankrupt years ago.

Nippon-Sharyo even builds EMU's here already, for the electrified Chicago service.

The FRA-compliant designs are in 1st generation. And it's harder when diesel-mechanical seems to be the consensus way to do FRA-compliants instead of diesel-electric where an AC traction motor doesn't care whether its electricity comes from a pantograph or an internal combustion engine as long as it's converted to the right voltage en route to the motor. I suspect it'll be 2nd (and for most manufacturers, 3rd) generation vehicles before you see that kind of modularity where conversion is anywhere near straightforward or cost-effective. Metrolinx thought about this, but those are heavily-customized FrankenMU's and the odds are vanishingly small that conversion is going to beat the price of all-new...especially when GO starts buying EMU's in mass quantities.

It's not even a consideration for the T right now. Even if these 1st-gen vehicles were modifiable, there's just no way conversion's going to be worth the cost. And they don't have to think about it for this first order. If Fairmount and Worcester get electrified...the DMU's can just go to Waltham and Reading. If they have any long-term desire to string up wires on those two lines with the frequencies to support it...this vehicle purchase changes nothing. Seriously...full-speed ahead. It actually gets the Indigo network expanded sooner the way the fleets would migrate around. And being 1st-gen vehicles, my guess is 2nd/3rd-gen are going to perfected enough that they will not opt for a rebuild of the 1st gens with old tech. Especially if they lick this hurdle with getting cost-effective diesel-electric motors that have a lot more in common with what the shops maintain on the loco fleet. If diesel-mechanical is just the bridge technology for present-day cost-effectiveness, they probably won't be interested in committing to it beyond the initial 20-year lifespan if traction DMU's eventually become more popular.

But there's nothing bad about this. This is the typical evolutionary path of 1st-gen vehicles. The 1st gen doesn't have the longevity of the perfected later models. And the first order is a small fleet, so the subsequent orders are eventually going to dwarf it and leave them as the less-flexible misfits. Sort of like the 1st-gen Boeings had no future once the Type 7's perfected modern Green Line LRV's, especially when they got outnumbered and couldn't trainline with the newer vehicles. They got displaced fast. And even if they had been less-lousy vehicles the retirement would've happened equally rapidly in favor of more sustainable later-gen equipment. It's going to follow that generational pattern (even if the 1st gen DMU's are orders-of-magnitude more winning vehicles than the 1st-gen LRV lemons).

If Metrolinx had been the lead customer for N-S, maybe things would be different, but I think the design was well down the tracks by the time Metrolinx bought the SMART options, not to mention that electric conversion was not part of the original plan but forced by political games.