MBTA Buses & Infrastructure

[Matthew]

One thing about the electric buses: it represents more than just another bus size. We're hoping that electric buses will eventually replace all diesel buses.

So it does make some sense spending some money now to try and get some experience in making them practical.

Getting away from the diesel engine mode is ultimately a very good thing for public health, even if they've served well to this point, and are better than a bunch of singly-occupied vehicles running around.

 

[citylover94]

Just curious why not just start using trolleybuses if emissions are the issue. Obviously it would require new infrastructure but it is a proven technology that operates very well. I am just curious if there are any reasons why it isn't being looked at as a solution more frequently?

 

[millerm277]

Just curious why not just start using trolleybuses if emissions are the issue. Obviously it would require new infrastructure but it is a proven technology that operates very well. I am just curious if there are any reasons why it isn't being looked at as a solution more frequently?

The infrastructure is considered ugly by some, you'll have NIMBY battles forever to string wires for it.

As a more minor concern any road with it also now has a maximum clearance height limiting moves of oversized items or at least making them far more difficult.

 

[The EGE]

There's a lot of pushback - some justified, most not - from residents about "unsightly" wires. That's why fast-recharge buses are the grand hope these days - they offer all the flexibility of conventional buses, require only point charging stations rather than wires, and yet are quiet and clean.

 

[BPLange7]

It does not make any sense for the MBTA to store, maintain and operate smaller buses. That's a whole new set of manuals and knowledge they have to train workers on. That's another set of vehicles that have to be swapped in and out, incurring costly deadhead time, whenever flexibility is needed.

It's bad enough to have to deal with 40-footers, 60-footers, and the dual-modes.

There just isn't enough savings from trying to micromanage bus sizes. And any savings you might find would probably be swamped by the costs of dealing with yet another bus fleet, and loss of flexibility. It would be terrible if you had to send out a 25-foot bus on a key bus route because that happened to be what was available at the terminus.

Labor, labor, labor is your major cost factor. A 40-foot bus driver costs the same as a 25-foot bus driver. (Now, a bus driver who had 40 feet, that might be a different story...)

If a contracted out company wants to run 25-foot "community shuttles" on the cheap, that's their business, but the T shouldn't get into it.

It also doesn't make any sense for the T to operate routes with low ridership and double digit costs per rider, but they do that anyway. If the alternatives are closing down the routes And leaving people without service or findin a way to do it for less cost, even 80-90% of the original (all-in considering all the direct, variable and incremental overhead you referenced), it's worth exploring. I'd personally prefer service cuts, but there's a large contingent that wouldn't.

Labor is a major factor. At worst you shift existing drivers down to the shuttles and pay them the same. At best you have a separate pay grade and save on labor.

 

[WormtownNative]

Cripes. WRTA just spent $7 mil (of grants) on 6 electric buses last year, to save $3 mil over the life of the buses.

http://blog.mass.gov/transportation/greendot/worcester-regional-transit-electric-transit-bus-fleet/

Only problem is that WRTA has only 1 charger bus port at their bus hub, and from what I hear they cannot do the hills of Worcester very well. Not sure how true that part about the hills is, but that's what I'm hearing.

 

[Matthew]

It also doesn't make any sense for the T to operate routes with low ridership and double digit costs per rider, but they do that anyway. If the alternatives are closing down the routes And leaving people without service or findin a way to do it for less cost, even 80-90% of the original (all-in considering all the direct, variable and incremental overhead you referenced), it's worth exploring. I'd personally prefer service cuts, but there's a large contingent that wouldn't.

Labor is a major factor. At worst you shift existing drivers down to the shuttles and pay them the same. At best you have a separate pay grade and save on labor.

The point is that they won't save any money and will probably cost more in the long run.

And don't forget: being stuck with the wrong kind of bus when you need to send out a trip -- right now -- is a cost too. It might not be counted the same, but it's a cost.

It's bad enough when they have to send out a 40-footer on a route that normally sees 60-footers.

 

[WormtownNative]

It's bad enough when they have to send out a 40-footer on a route that normally sees 60-footers.

Could be worse.

 

[Matthew]

While we're on the bus topic, city reps claimed, last night, that they are actively working on transit signal priority for the 57 bus as a pilot. Supposedly Babcock street signal has already been wired up as a test, up and running.

 

[Alon]

Only problem is that WRTA has only 1 charger bus port at their bus hub, and from what I hear they cannot do the hills of Worcester very well. Not sure how true that part about the hills is, but that's what I'm hearing.

That's strange; usually, electric vehicles are better at climbing hills. Usually if a city's kept some trolleybuses it's because of hills, as in San Francisco, and not because they converge on an underground terminal as at Harvard Square.

 

[The EGE]

Trolleybuses are better at hills because they have the constant supply from wires. You can just dump raw overhead power into the motors and the only limit is that of the motors themselves. Batteries and capacitors can only discharge so much at any moment, and high discharge rates will obviously shorten how long the bus can run on the battery.

 

[whighlander]

Trolleybuses are better at hills because they have the constant supply from wires. You can just dump raw overhead power into the motors and the only limit is that of the motors themselves. Batteries and capacitors can only discharge so much at any moment, and high discharge rates will obviously shorten how long the bus can run on the battery.

Batteries are fiendishly heavy for the amount of energy that they can store and also the power that they can deliver. They also take a very long time to refill them compared to liquid fuels with equivalent energy content.

That's why gasoline and diesel replaced batteries and steam about 100 years ago -- not a conspiracy -- just physical chemistry and economics

While batteries have gotten better -- so have internal combustion engines and the gap is not closing -- indeed there are R&D projects to allow fuel to be "burned" [e.g. microturbines, thermoelectric], or electrochemically oxidized [e.g. low or high temperature fuel cells] in portable devices to extend their off-the-wire lifetimes.

Fuel cells are an alternative to batteries -- but they are still expensive to purchase and operate unless they are fed with laboratory grade clean hydrogen [beset with its own problems of volumetric and other storage issues]

The one big advantage that buses and EMU's have over passenger vehicles is that the extra weight of batteries, or the extra-cost of fuel cells can be accommodated

 

[Matthew]

^ yup, power to weight ratios rule.

That's why EMUs and trolleybuses are awesome. It's like having a massive power plant hooked up directly to your vehicle with none of the weight. Because that is what it is.

 

[The EGE]

Using supercapacitors (which can dump a huge amount of power) versus batteries (which are current limited) will certainly help as the technology matures.

 

[whighlander]

Using supercapacitors (which can dump a huge amount of power) versus batteries (which are current limited) will certainly help as the technology matures.

EGE -- Ultracapacitors are interesting but yet unproven as to lifetimes in high energy / high power applications

To make a capacitor efficient at storage you need a thin layer of high dielectric content as traditional dielectric materials such as paper and plastic films are just too thick

The problem is that as you get thinner the electric field [voltage / thickness] gets progressively greater and that encourages destructive processes such as electromigration and punch through

Before we can afford to spend B$ on ultracapacitors for Big Scale applications the reliability, failure modes and MTBF need to be better understood

Same thing is true with liquid metal electrochemical energy storage technologies -- look promising -- but unproven

 

[Alon]

Batteries are fiendishly heavy for the amount of energy that they can store and also the power that they can deliver. They also take a very long time to refill them compared to liquid fuels with equivalent energy content.

Sure, but they still have better performance. Electric cars do not need multiple gears, and this gives them much higher acceleration rates. Electric car manufacturers are mostly targeting the green crowd, just like hybrid manufacturers, but there's also a niche for high-performance luxury.

 

[HenryAlan]

No it doesn't.

Starting in april, commuter rail monthly passes will just be printed in ink on charlie cards. There will still be no actual acceptance of Charlie on commuter rail.

True, no stored value Charlie payments -- I misspoke. I was thinking more about the commuter passes now doubling as tap and go cards for people who also ride subway or bus. In particular, this will be a huge improvement for people who buy 1A passes.

 

[HenryAlan]

The infrastructure is considered ugly by some, you'll have NIMBY battles forever to string wires for it.

As a more minor concern any road with it also now has a maximum clearance height limiting moves of oversized items or at least making them far more difficult.

They are also much worse for bunching. Any high frequency corridor will typically have buses passing one another at alternating stops. This practice can't be followed on trolley buses, so dwell times on the first bust get drawn out longer and longer, while less crowded busses stack up behind it.

 

[Matthew]

The same applies to trolleys and trains. The first answer is: don't get yourself into that situation in the first place. Make boarding fast and easy, get signal priority, don't let the buses bunch. The second answer is: express the one in front.

But just because diesel buses can pass each other doesn't help them with bunching. Remember, the nature of bus bunching is such that it 'gravitates' vehicles together. It doesn't matter if one bus can pass another one, because then the bus that is now in front gets delayed at the next bus stop, while the bus that is now in rear plays leapfrog again. And so on.

The best medicine is prevention.

 

[Alon]

They are also much worse for bunching. Any high frequency corridor will typically have buses passing one another at alternating stops. This practice can't be followed on trolley buses, so dwell times on the first bust get drawn out longer and longer, while less crowded busses stack up behind it.

There is a limit to bus ridership, beyond which buses bunch as you mention, but no bus route in Boston is even close to hitting it. New York has multiple bus routes in the 50,000 weekday riders region. Vancouver has a route with more than 50,000. These are all at the limit of what buses can do, with frequent bunching, but at the same time, Boston's busiest bus has 16,000 weekday riders.

In Vancouver, on corridors with local and limited-stop buses, the local buses are trolleys and the limiteds are diesel. Vancouver's busiest bus is the diesel limited 99, but the second busiest, the 20, is a trolley, with 27,900 weekday riders. The 8 and 3 are trolleys with 20,000 weekday riders each, and a substantial shared inner segment, before they diverge and serve two parallel arterials. The shared segment has countdown clocks telling people when the next bus of each route will come, and it seems to work.

I do not think the 20, 8, and 3 have signal priority. I know for a fact that the 99 and the third busiest bus route, the 9, which runs in the same corridor, do not, although the corridor does give through-traffic priority over intersecting traffic. None of these routes, except the 99, has POP. However, the bus fleet is 100% low-floor, which speeds up boarding. Moreover, there are monthly passes, and most passengers board from the front and show them to the driver quickly, without needing to insert or tap a card.