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  • 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

 #981121  by CRail
 
Wire is strung from a coil. When it breaks or is cut it is spliced together at the break. The MBTA's trackless lines have been up for so long I'd be suprised to see a continuous section of more than a couple thousand feet. If you look closely, you can see the splices on the wire quite often, sometimes 2 or more right in a row. It's also clamped to the hangers and can break away fairly easily. In many cases, when there's "wire down," none of it touches the ground, it's just a broken hanger allowing the wire to droop a lot. In Watertown's case, the wire was DOWN, including runing wire, span wire, special work, and hardware. It would take some serious force to pull down a line pole though.
 #981239  by FatNoah
 
I forgot to mention that yesterday morning it looks like a trolley making the turn from Main St. to Mt. Auburn got snagged and took the wire down. Crews were out yesterday AM and fixed the wires. There's noticeably less droop in the wires than after the first repair.
 #1156328  by Myrtone
 
How about trolleytrucks, has anyone ever heard of these, does anyone here own a private electric car (driven in a city with trolleybuses), and if so have you thought of fitting trolleypoles to your car (and an on-board power consumption metre) and seeking permission from the trolleybus operator to use their wires when driving along their routes, such a car would still retain its batteries but they would only be used for off-wire driving.
 #1156357  by djlong
 
Non-starter.

The pole would have to be HUGE to go from the car's height to the wire - a car being a LOT shorter than a bus.

Passing would be an enormous hassle. Your car wouldn't be making all the stops the bus makes and you'd be stuck behind the buses unless you want to get out and de-wire and wire for ewach pass - oops, the bus started up while you were doing that!

You'd be limited to Dayton, San Francisco and Boston.

This is why hybrid cars have internal combustion engines instead of poles. (And why research is going into putting induction plates in roads for on-the-go charging)
 #1156367  by Myrtone
 
djlong wrote:The pole would have to be HUGE to go from the car's height to the wire - a car being a LOT shorter than a bus.
The trolley plose base could just be mounted futher foward, that would reduce the problem, and I'm sure that a typical North American Minivan may just be long enough to accomodate it.
djlong wrote:Passing would be an enormous hassle. Your car wouldn't be making all the stops the bus makes and you'd be stuck behind the buses unless you want to get out and de-wire and wire for ewach pass - oops, the bus started up while you were doing that!
But you would surey have powered raisng and lowering of poles! Just as newer trolleybuses do! You are correct in that even a taxi would not be making all the stops that bus is making, but since modern trolleybuses have powered trolleypoles, why not just lower these whenever stopped (for any considerable length of time)?
djlong wrote:You'd be limited to Dayton, San Francisco and Boston.
You wouldn't with auxillery power units.
djlong wrote:This is why hybrid cars have internal combustion engines instead of poles. (And why research is going into putting induction plates in roads for on-the-go charging)
A dualmode straight-electric hybrid electric drive would offer the same flexibility while using external electricity where available.
 #1156379  by Disney Guy
 
Myrtone wrote:How about trolleytrucks, has anyone ever heard of these, does anyone here own a private electric car (driven in a city with trolleybuses), and if so have you thought of fitting trolleypoles to your car (and an on-board power consumption metre) and seeking permission from the trolleybus operator to use their wires when driving along their routes, such a car would still retain its batteries but they would only be used for off-wire driving.
Yes trolley trucks do (did) exist. They were used in private industrial locations such as quarries and not intended for use on streets with trolley bus wires. I am guessing that they were used where the terrain was really hilly.
Some were dump trucks. Either they had to have diesel or gasoline engines as well, or were restricted to a "line haul" route where loads were transferred to them at one end of "the line" and they looped or wyed and unloaded and required reloading the cargo (using diesel front end loaders?) onto non-trolley trucks at the other end of the line.
 #1156409  by MBTA3247
 
Myrtone wrote:
djlong wrote:The pole would have to be HUGE to go from the car's height to the wire - a car being a LOT shorter than a bus.
The trolley plose base could just be mounted futher foward, that would reduce the problem, and I'm sure that a typical North American Minivan may just be long enough to accomodate it.
djlong wrote:Passing would be an enormous hassle. Your car wouldn't be making all the stops the bus makes and you'd be stuck behind the buses unless you want to get out and de-wire and wire for ewach pass - oops, the bus started up while you were doing that!
But you would surey have powered raisng and lowering of poles! Just as newer trolleybuses do! You are correct in that even a taxi would not be making all the stops that bus is making, but since modern trolleybuses have powered trolleypoles, why not just lower these whenever stopped (for any considerable length of time)?
djlong wrote:You'd be limited to Dayton, San Francisco and Boston.

You wouldn't with auxillery power units.
djlong wrote:This is why hybrid cars have internal combustion engines instead of poles. (And why research is going into putting induction plates in roads for on-the-go charging)
A dualmode straight-electric hybrid electric drive would offer the same flexibility while using external electricity where available.
A regular trolley pole is already longer than the roof of a minivan. One long enough to reach the wires from the height of a minivan would stretch several feet behind the van when it was down, even if it was mounted to the hood of the car.

Powered trolley poles can only be raised at locations with plastic panels placed around the wires to guide the poles into position, and the vehicle has to be properly positioned underneath them for that to work. Elsewhere the poles have to be raised by hand, which can take up to several minutes. AFAIK, Silver Line Way is the only place in the Boston area where powered poles can be raised on their own.
 #1156433  by Myrtone
 
Frist of all, the trolleypoles on regular trolleys are much closer to the rear than the front, so I have noticed. And also see a video on this page, at one point, one can see as many as three-pairs of wires all serving the same direction, so one idea i for every bus stop along a trolleybus route to include either an overtaking loop in the wires and/or a re-wiring trough, this wolud make it easier for trolleybuses to leapfrog, and would be important if trolleytrucks went along these routes.

Also, where is Silver Way?
 #1156453  by jbvb
 
A long time back, seems like it was the early 1970s, an MIT professor fitted out a VW bus with trolley poles so he could test an automatic wire-seeking servo setup. I don't recall the VW bus actually having electric propulsion. Presumably this was done with the T's permission.
 #1156689  by MBTA3247
 
Myrtone wrote:Frist of all, the trolleypoles on regular trolleys are much closer to the rear than the front, so I have noticed.
Yes, and when the poles are down the ends extend no more than a foot beyond the rear bumper. Poles sized for an automobile would extend several yards past the rear bumper when tied down, which is never going to pass muster with the DOT.
so one idea i for every bus stop along a trolleybus route to include either an overtaking loop in the wires and/or a re-wiring trough, this wolud make it easier for trolleybuses to leapfrog, and would be important if trolleytrucks went along these routes.
Never going to happen. TTs have to go slow through special work to avoid dewiring, so adding passing loops at every stop (remember, many stops are only a block or two apart) would have a net effect of slowing down the entire route. On top of that, the frogs would either be set based on current draw in the section immediately before the loop (in which case everyone using the wires has to know the trick for throwing them in the proper direction), or they would be normally set to one route and someone wanting the other route would have to stop and get out to push a button on the nearest pole.

Have you actually put any thought into the actual utility of adding trolley poles to trucks or automobiles? As someone already mentioned, there's only a handful of cities in North America that have TTs, each with only a handful of routes. Given that a truck or car is typically only going to spend a short (if not completely insignificant) part of a trip running on the same road as a TT, the minuscule environmental benefits of running as an electric vehicle for those few blocks are outweighed by the cost of installing trolley poles on said vehicle and the longer time needed to traverse that segment of the vehicle's route.
Also, where is Silver Way?
South Boston.
 #1156705  by sery2831
 
Just a side note. Silver Line Way is a 100% private way for MBTA vehicles.

Also the risk of private vehicles causing damage to the overhead would be too great, and this would disrupt the passage of coaches that need to use the overhead to get people to their destinations.
 #1156756  by Myrtone
 
MBTA3247 wrote:...when the poles are down the ends extend no more than a foot beyond the rear bumper. Poles sized for an automobile would extend several yards past the rear bumper when tied down, which is never going to pass muster with the DOT.
But how far do the poles extend from the actual base? Private vehicles can be as long as six metres, like many 1960s Cadillacs, and maybe even the larget minivans today.
TTs have to go slow through special work to avoid dewiring, so adding passing loops at every stop (remember, many stops are only a block or two apart) would have a net effect of slowing down the entire route. On top of that, the frogs would either be set based on current draw in the section immediately before the loop (in which case everyone using the wires has to know the trick for throwing them in the proper direction), or they would be normally set to one route and someone wanting the other route would have to stop and get out to push a button on the nearest pole.
This may be true of wire switches, and surely some design improvents would enable withstanding higher speeds, but what about re-wiring troughs, what if some stops have rewiring troughs and others have loops? You could surely use a signal from the direction indicator to operate the switch.
Have you actually put any thought into the actual utility of adding trolley poles to trucks or automobiles? As someone already mentioned, there's only a handful of cities in North America that have TTs, each with only a handful of routes. Given that a truck or car is typically only going to spend a short (if not completely insignificant) part of a trip running on the same road as a TT, the minuscule environmental benefits of running as an electric vehicle for those few blocks are outweighed by the cost of installing trolley poles on said vehicle and the longer time needed to traverse that segment of the vehicle's route.
You use to have a lot more, so I've heard, much of it was abandoned for dubious reasons.
 #1156844  by djlong
 
I'd forgotten about Seattle's relatively new tunnel, but I never knew about Philly - and that's bad as I go to Philly to visit my daughter! I *should* have known that one...
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