Translink trolley car observation
Posted in Commentary on April 16th, 2007 by Sacha PeterTranslink bought a whole bunch of new trolley buses, the ones with the poles in the back that extend to the electrical wiring above. They are painted in blue so they are really easy to spot. Sometimes you see bus drivers driving past intersections too fast and the poles detached from the back and the driver has to put the wires back onto the bus again.
However, today I saw something a little different. There was a fresh car crash at the intersection of Seymour and Davie. I didn’t see the crash but since there were no police there, it was obvious it was new. I’m guessing that an SUV was travelling south on Davie and made a left turn onto Seymour, but the person heading north on Davie headed straight and they crashed into each other. It was a low velocity crash, but both of those cars were probably totalled. They occupied the middle of the intersection.
So on the north side of the intersection was a trolley bus. It wanted to turn left onto Seymour, but the poles could not stretch far enough in order for the bus to make the turn properly, as the cars were below the wires. I then saw the bus detach the wires on its own, and then move slowly and make the turn manually without the power from above. The bus then drove east on Seymour for a little bit, clearing the intersection before it stopped and the driver got out to put the poles back on the wires again.
I didn’t know the trolley buses had this capability, to drive small distances without the use of power from the wires above.
Yup, they have battery packs. The older trolleys, still on the road, can do this too. I’ve seen it where a transit worker on the street will pull the poles down, hook them in, then the bus will drive past an obstruction (or more likely, work on the power lines), then a worker on the other side will unhook the poles and re-attach them. I’m surprised when some drivers stop in the intersection to re-attach the poles: why not drive ahead a few meters to the curb?
(I can actually see how it might be paradoxically safer to do it in the intersection: that way drivers intending to turn right can see the bus and its driver outside in time to stop.)
Based on a discussion I once overheard between two drivers (one of whom had just missed his official turn), the buses don’t have much of a range on those batteries. Trying to go around the block to correct the course was considered to be a pretty dicey proposition.
And I bet that they fix the poles in the middle of the intersection because they are worried about getting tangled and tearing something down. Electrocuting a couple pedestrians probably doesn’t look good on the performance review :-)
Many cities have auxiliary power packs on their trolleys. Some use small diesel generators. As noted the battery packs provide only low speed and limited range. I would like to see hybrid buses with poles added in Vancouver to extend the range of some trolley routes without the need for stringing more wire (which costs over $1m per km) – for example on route #41 to UBC. Or extending the Broadway #9 to Brentwood.
Hybrid vehicle engines are not designed for what you mention – for example, if you are driving a Prius (or presumably any other vehicle with a hybrid engine) if you run out of gas, that’s pretty much it – if you keep driving with it and you’ll get around a couple kilometers, but the deep discharge will kill your batteries (120 pounds worth).
It takes a huge re-design and a LOT more in terms of batteries (prohibitively more from an economic standpoint) to do what you’re proposing to trolley buses. The problem essentially deals with power conversion – the transfer from the lines to the batteries and back into mechanical power is really, really expensive. When you detach the power lines, it’s like running a Prius without gasoline.
It’s a different story if you give them diesel engines and gasoline, but that kind of defeats the purpose.
Not at all. If you put poles on hybrid buses you already have the power set up to run off wire. But with much less fuel consumption (and hence emissions) than a conventional diesel. On the other hand when the hybrid is under the wires, it can put its poles up and shut off the diesel altogether. No, I won’t give them gasoline either, since diesels don’t like it. Actually the most efficient way to turn oil into motive power is the diesel electric railway locomotive. Now a hybrid bus has rubber tires on pavement so there’s lots of energy loss there, but its still a lot better than the conventional transmission. Actually I would like to see both trolleys and hybrids running with hub motors but I suppose that is still a few years away.
So no. Some redesign possibly but not lots of batteries. Just a little engine and good gen set. And maybe an adjustment to the control software. The same amount of batteries as already installed in hybrid buses.