MBTA Bus & BRT

HelloBostonHi

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1294 isn't even a BEB. It's an extended range hybrid. It's set purpose is the silver line and potentially routes that use the Harvard busway. There are no other uses for that type of technology in Boston. It offers no real material benefits over the current hybrids in use beyond zero emission running in tunnels. And once again you're completely and utterly missing my point. I have no interest in jumping head first into a full BEB fleet. However, a BEB fleet is absolutely cheaper and simpler to implement than full CR electrification. That was my point. It's clear that it's completely missed you.
 

F-Line to Dudley

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1294 isn't even a BEB. It's an extended range hybrid. It's set purpose is the silver line and potentially routes that use the Harvard busway. There are no other uses for that type of technology in Boston. It offers no real material benefits over the current hybrids in use beyond zero emission running in tunnels. And once again you're completely and utterly missing my point. I have no interest in jumping head first into a full BEB fleet. However, a BEB fleet is absolutely cheaper and simpler to implement than full CR electrification. That was my point. It's clear that it's completely missed you.
Your 'point' was an incoherent apples-broccoli modal comparison that has no basis in the real world. Battery-electric buses could not be any more alien to electrified rail. One draws power from internal source/storage, one from an external source. One runs on a fixed guideway, one does not...which makes all the difference in the world value-wise to where the power supply is located. Then there's the orders-of-magnitude differences in scale: the tractive effort required to run the vehicle, and the number of bodies hauled for that effort. Yes...your strawman missed its target because they don't do remotely the same thing for the same purpose.

And there's nothing "cheaper" about miscalculating your fleet margins by a third or more because of grave blind spots re: battery charging ranges on one's route network. Government lives in a world of budgets, and degree of overspending vs. estimate cripples public services way harder than the absolute dollar figure itself. When the pricier overall project hits its cost targets more reliably than the "cheaper" one that blows its budget to shreds, it's the "cheaper" one that's going to have much steeper and longer-lasting negative impact on services. Applied to this incoherent apples-broccoli comparison of yours, that means the railway electrification with a codified federal specs book for 25 kV overhead power and 100 years of worldwide best-practices to lean on is extremely more likely to stay within budget because the lineside costs are very nearly fixed (i.e. it's components and making accurate property valuations where that comes into play) while the vehicle-side costs are no riskier than any generic train procurement (i.e. subject more to degree of overcustomization attempted than any unknowns about what it's made of). A major unforeseen cost blowout there is pretty clearly going to finger project management incompetence, not the technology. Not so with a BEB fleet, because the cities that have done OK with this current technological generation and the ones who've whiffed the reference margins by 30-40% have not even begun to figure out why there's such a gaping discrepancy in the technology's performance city vs. city. It's having to be papered-over in places like Shenzhen with heaploads of debt-spending. That's completely lethal practice in most of the rest of the world. The fact that these cities cannot explain the entirety of why they miscalculated so badly is the major indictment of this generation of BEB's, and why slow-walking it to the next generation is looking far more prudent. You can't find a railway analogy at all there, because this is like the equivalent of mis-designing the power source vs. projected schedules to the point where the whole works browns-out all day...and that simply doesn't happen when lineside power installation is century-perfected science.

So, yeah...crow on more about the top-line dollar figure as if there's a point there. It doesn't matter, because the only thing the officials with a stake in the 4-year CIP care about is "actual" vs. "projected" and how likely that's going to spring a humongous leak over the course of that budgeting window. We can pay for expensive things just fine when they score high enough on their value proposition to make a budget pitch that'll stick; that's no problem. But you know damn well it's the overruns, not the top line, that hinders public services, kills political careers, and angries up the voters. Boston coined its own budget hangover "syndrome" based on the overrun antics of its most infamous public works project. If you haven't closed up an uncertainty gap in "actual" vs. "projected" that's big enough to drive a 60-footer through, pols and bureaucrats get very risk-averse very quickly. The only BEB adoption statistic that the folks putting up budget money care about is "actual" meeting "reference" on the performance specs, and isolating the precise reasons for huge city-by-city discrepancies so those can be refactored into the reference specs and the budget...then waiting for the next 1-2 gens of vehicles to close the technological gap enough that budgeting certainty can reign. We can start electrifying substantial parts of commuter rail the second they can peg the staging on a CIP; the only way that's going to blow out its budget is from purely self-inflicted wounds. Literally nothing else about the two modes has anything to do with the other, and the top-line price of apples vs. the top-line price of broccoli is irrelevant.

The only thing that matters is do apples stay within their budget, and does broccoli stay within its budget.
 

whighlander

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Regenerative braking doesn't really care what speed you're stopping from or how often, it works on simple energy conservation formulas at the end of the day. And the MBTA already has tons of data on it, every hybrid mbta bus uses regenerative braking.
Wrong!-- Google Michael Faraday or pull the trigger on a variable speed drill while holding onto the chuck

Regenerative braking occurs when the kinetic energy of the vehicle is put back into the battery [or the external power system] -- but in reality its the rotational energy of the wheels being converted into electrical energy by using the motors as generators. -- this is known as electrodynamic braking

This in electrodynamic braking -- if the wheels are not turning there is no generation -- and as the wheels turn faster the generation increases or vise versa as the wheels turn slower the generation decreases. To be regenrative the generated energy is used to recharge the batteries or fed back into the power supply through an overhead centenary or a third rail. The path from the generation to regenerative requires control electronics and lots of wiring all of which have electrical losses converting electrical energy to heat.

Eventually losses in the system means that there is no net transfer of energy to the battery [or external power system] -- at that point regenerative braking is useless. Note that you can continue to extract energy from the wheels at ever decreasing amounts as long as you just dissipate it as heat in a resistor. *1

However -- At some point the residual rotational energy can only be dissipated by friction [traditional brakes] if you want the vehicle to come to rest in a controlled manner

*1 -- the people who designed the PCC cars nearly 100 years ago knew all this except that they just used the generated electricity to brake electrodynamicly by dissipating the energy into a big honking resistor" -- it was electodynamic braking -- but not regenerative. At the end of the electrodynamic braking a cylinder pushed a brake shoe against the wheel
 

HelloBostonHi

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F-line, if you go back my apples to broccoli comparison was in response to jass asking why the MBTA is treating bus electrification differently than rail electrification. My response stated that it was because they are two completely different things. You've completely misunderstood me here, so I'm not even going to read that crap pile of text above this because it's based on inherently flawed interpretation of what I was saying. I rest my case, let's get back to discussing buses for the Christ's sake.


What is the "Alewife Access Ramp" mentioned as a planned 2019 project?
Noted on the MBTA alerts today that "On Saturday, October 19, the main entrance to the Alewife parking garage will close and temporarily relocate for repairs and upgrades."

Perhaps a correlation?
 

F-Line to Dudley

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F-line, if you go back my apples to broccoli comparison was in response to jass asking why the MBTA is treating bus electrification differently than rail electrification. My response stated that it was because they are two completely different things. You've completely misunderstood me here, so I'm not even going to read that crap pile of text above this because it's based on inherently flawed interpretation of what I was saying. I rest my case, let's get back to discussing buses for the Christ's sake.
Your original response stated that BEB's were "ready to roll" while railway electrification was not, and tried to justify it with very spurious comparison of the top-line complexity of completely alien projects with completely alien amortization rates for paying off their investments. Don't mistake criticism of a deeply, deeply flawed argument rife with factual inaccuracies for "misunderstanding". Start by turning that personal aversion to crap piles of text to a little more self-awareness, first.

When you have real-world BEB installations that are missing their range targets by 30%+ in some cities but not others and no one has a good enough idea why to prevent the same mistake from happening, they aren't "ready to roll" on a wide scale. At all. There is no other modal comparison that fits, because no other mode is going through the technological growing pains of BEB first-adopters. You tried to twist an over-optimistic take on BEB suitability into direct comparison with unfinished decisions in the RER implementation study--which is still answering existential questions about what strategic direction they go, NOT what they could buy after they decide--as if those were question marks about the technology itself and product availability. That's utter bunk. This, this, and this have sterling service reputations in electric push-pull and are catalog-orderable right this second; the latter's compatible EMU power car variant is already on-order for large quantities from 2 agencies. There'd be more to shop around if Caltrain weren't running its Stadler KISS order of EMU's straight into the ground with dual-height door overcustomization and running the risk of having to cancel the order. Other Euro import possibilities also await under the new FRA regs if they don't want to take the easy/least-customizing way out by ordering 200 MLV's for the upcoming procurement then laundering some slush NJ Transit options to plug some EMU power cars into those coaches. Lineside it's all world-generic components following a federal specs manual...and infrastructure that fits entirely on the ROW property except for 30-mile spaced substations, to counter your wild overestimates of required property acquisition.


Then we've got this whole top-line cost fixation bereft of any underlying context. Yes, the whole package for CR electrification is expensive because--shocker!--it's an enormously higher-capacity mode shooting for an enormously-higher range. An armada of 20 BEB's doing Boston-Worcester at evening rush at equivalent of one Worcester train's capacity is not surprisingly going to have a vastly higher top-line price tag for adoption than just working some Key Routes in the Yellow Line's home district. Pricey lineside electrification also has decades-longer longer shelf life than the vehicles that run below the wire, with externally-powered vehicles longer lasting than their internally-powered counterparts (witness: TT's with a reliable lifespan of 25-30 years while all other buses are pretty thoroughly shot around 15 years), with readily midlife-rebuildable stock than buses that are slated to move to a more disposable 12-year replacement cycle. And given the rapid evolution of battery power, the garages (and possibly even the offline charging tech) are going to have to be re-equipped more frequently with each generation. Amortization ends up almost as important in the long run as top-line price on the initial capital procurement. That should be self-evident, but apparently not.

As before, we have no problem paying for pricey things if they are stepped out in advance on a CIP and can hold to their budget. We have enormous difficulty paying for things that blow out their projected budgets by several orders of magnitude. GLX pre- and post-reboot pretty much tell both sides of that story. The whole conundrum with 1st-gen BEB's is the debt-spending cities like Shenzhen--which even the Chinese gov't said "Enough is enough" on bailing out the overruns--are having to do covering the range shortfalls of their early-adopter fleets. And why no one's been able to wrap brain with certainty over why some cities have fared so very very poorly on charging ranges while some using the same bus makes have done better. It is pretty hard to see how railway electrification--higher top-line price and all--has similar catastrophic blowout potential unless we mismanage it two hands around necks like Caltrain is doing on all facets--lineside and vehicle--for its project. The smaller (but let's be clear: it's still all high-stakes $$$) top-line project that can't hit its projected budget on a dartboard is going to wither under scrutiny vs. the pricier (but 1000% differently-amortized) project that has little guesswork and a dead-easy chain of project mgt. blame if it does blow its budget.


That does not mean these projects SHOULD be compared...at all. Attempting to compare them is how the crap piles of text started flowing in first place. But if you are going to attempt to compare, exercise a little bloody context about the gigantic honking differences between the two and refrain from cherry-picking superficial garbage factoids.
 
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Arlington

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I see 14th St in NYC as being analogous to Congress St from Bullfinch Triangle to B St in the Seaport. I'd love to see a car ban on it in favor of bus, bike, delivery & "car pick up and drop of only"

Bus from NS/Haymarket to Seaport would be the missing link from everyplace that isn't South Station or the Airport.

 

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