Close - Horachek.

The story as I remember it (I think published in 1982) involved not just the existence of field shunting but the addition of loading coils to compensate for back EMF in the motors at higher speed. Reportedly the test 'Liner happily got up to 108mph -- on 28" wheels! -- and in the story that, not grade-crossing activation length, was the reason the loading coils were summarily torched off almost immediately on conclusion of the test run. (The author indicated that the torched-off ends were still visible at the time of his writing; they might still be!)

I would be interested in the technical reasons why the Electroliners were run at about 85mph peak speed while some of the 'regular' cars were allowed 90+. I suspect this might have something to do with the longevity of the special right-angle gearing from the motors.

Was not the 97mph speed running with a Cincinnati car done with poles? That would have been interesting to see (as would the various sorts of maintenance, to poles and electrical gear alike, when cars like that were regularly run 'in competition' at those speeds!)

Not to be a pick, but I thought that was the definition of a field shunt. The older way of doing it was called a field TAP, just an extra tap brought out of the winding to allow less of it to be used at high speeds; the classic "short field". Field shunts added extra resistance to the field winding circuit and accomplished the same thing while allowing the whole winding to be used.

The other interesting comment in the article was that if the trains had been equipped with 36" wheels (not really a stretch, mechanically) they should have been capable of 125 MPH.



According to museum founder and former North Shore motorman Howard Odinius, they were limited to 85 MPH because that's all they could do. Howard was not really a fan of the 'Liners.

Were the North Shore's trolley pole springs adjusted to put increased pressure on the trolley wire to allow for the high speed?

It is; I think the 'ballast coils' were constructed as 'barretters' to give appropriate control based on temperature, limiting the amount of 'shunt' as the temperature in the coil wire increased. I think I was assuming that the coils were somehow providing reactance to a commutated field current, but how likely is that? There are many here who know much more than I do about practical field weakening in traction motors... and correct nomenclature therefor.

Right angle gearing???? HUH?
Having been present when one of the Electroliner's motors was pulled out, I can assure you there is no right angle gearing present.
[edit]
The drive train consists of a traction motor mounted rigidly (not nose-suspended) to the truck frame for every powered axle, parallel to the axle, the Westinghouse-Nutall flexible coupling, and a nose suspended gearbox
[/edit]
Perhaps you are thinking of a CTA 6000 series?


Jeff

I could swear that I remember the Electroliners having those lightweight hypoid gearboxes!

I have no idea, utterly no idea, what I could have been thinking about.

In response to dinwitty, the North Shore Line had catenary on the Skokie Valley route and on its older route to a point north of Waukegan. But from there to the outskirts of Milwaukee, the overhead was simple suspension, and the trains operated just as fast as they did on the Skokie Valley route. I rode NSL many times in its last few years, and there's no question the trains were operated wide open on the non-catenary segment - you could see the controller position from the "railfan" seat on the conventional cars.

There's a commercial railfan film that shows a northbound NSL train making the 3rd rail-trolley transition with poles being raised in motion. I think it may have been a Sunday River production, but I'm not sure about this.

You can do it if you don't mind missing a lot. You have to keep good control on the rope, letting it fly up into wirework could break your pole and/or tear the wire down.


Never been on the 5-Fulton after midnight, clearly! :)

I also have a hunch the folks in Crimea get some speed up on the trolleybus to Yalta. That's a mighty long run.

Since the North Shore was pole, not pantagraph, the wire would not be offset pole to pole to curb wire wear, it would be steady usually. So vs any car rocking and some wire wobbly, its a cleaner shot, but clearly a skill required.

In response to the notes about how the North Shore was able to reliably make the transition from third rail to trolley pole at speed, the technique is relatively straightforward: (1) When raising trolley pole, do it with the minimum amount of horizontal movement needed to move the pole away from the trolley hook, to prevent the pole from swinging from side to side, (2) hold the pole just below the trolley wire. (3) stab the pole upward when it seems to be aligned with the trolley wire, but don't let go of the trolley rope unless you know you've hit the wire, (4) if you miss, try again. Obviously, it required skill, but it wasn't a great difficulty (and it was performed successfully many times a day)

On NSL, the third rail-trolley changeover point was under catenary centered over the rail and there was some distance between the trolley wire and any wires the pole could foul. So there was little risk of the pole fouling the overhead if the trainman missed the wire, (so long as he kept the pole from getting too high). Also, while the changeover was done "at speed", it wasn't done at anywhere near maximum speed. My recollection is that it was usually done at about 40 mph or so.

The process involved more than just raising the trolley pole. Each motor car had a trolley-third rail knife switch the trainmen had to operate to change from third rail to trolley, or vice versa (the purpose was to deactivate the third rail shoes, so they weren't a hazard to someone who might inadvertently come into contact with them on the overhead wire segments of the railroad). The procedure required the motorman to shut off power when approaching the changeover point. As each trainman raised his pole and operated his changeover switch, he would give a bell signal to the trainman on the car ahead. That trainman, once he had raised his pole and set his own changeover switch, would then give the same signal to the trainman in the car ahead of him, and so on. The motorman would not begin to power until he got the bell signal from the car immediately behind him (or his car, if the switch was on the opposite end of his car).

Ah, for the good old days.

My understanding is that wire for panagraph operation was offset to cause a wide wear location on the graphite on the top of the panagraph -- not to curb wire wear. If the wire was not offset over a number of poles and then back again a narrow groove would be worn into the graphite and could cause a snag between the wire and the pan.

yehwell, curb wire wear, slow it down, yah knows...from pole to pole it wiggles left and right or you wear a slot. South Shore might carry extra pan flaps for emergency, but you just flip the pan to the other end till shop time.

mmm...pantagraph...nudge....

Another factor when using trolley wheels is that the wheel must be balanced. A 6-inch diameter wheel will be rotating at about 1600 revolutions per minute at 30 miles per hour.

If the wheel is out of balance it will "bounce," cause arcing between the wheel and the wire, leading to severe wheel damage.

For many years, the Western Railway Museum has been carefully balancing all trolley wheels (including new ones received from manufacturers) to avoid this problem.