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The Bi-Pass: 1908

The Bi-Pass: 1908

Holyoke, Massachusetts (vicinity), circa 1908. "The Bi-Pass, Mount Tom Railway." Here we see the railway's two "elevating cars," named after Rowland Thomas and Elizur Holyoke. 8x10 glass negative, Detroit Publishing Co. View full size.


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Mt. Tom operation explained

Comments from H. Raudenbush:
I think I just figured it out. It definitely falls under the heading of a Austrian saying “Warum den einfach wenn komplizierte auch gehts” (Why make it simple when it can also be complicated)

It’s a counterbalanced trolley rig. Each car has traction motors, but the grade is too steep for normal adhesion working, so the cars are tied to the two ends of a cable. The cable must pass over a sheave at the top of the line, but unlike a funicular/incline, that sheave is not powered.

At the passing siding, the rope for one track has to cross rails of the other track. This is done crudely, by having a gap in the closure rail of the turnout. To get the car over this gap, the overhanging wheel is picked up by an auxiliary rail, which is probably higher than the normal rail. You can see the auxiliary rail beside the gap in the running rail.

The car hides the switch points or equivalent. Since the frog has flangeways, it appears that the normal wheels on both sides have normal flanges. (On some funiculars, each cars has double flanges on one side, no flanges on the other side. Then neither points nor frog are needed at the turnout).

You can see the cable attached to the near car, and the carrying sheaves for the cable along the track.

Those wires bracketed beside the track must have some function, but I’m not sure what. Possibly contacted by a shoe on the car, maybe they control the switch points. With the two cars at the ends of the cable, no signals are necessary (as long as the rope doesn’t stretch too much!)

That angle iron on a big timber in the middle of the track beside the cable, might be the equivalent of a Fell Rail, used for braking; brake shoes could clamp to it and provide braking independent of wheel-rail adhesion.

Sound plausible?


The type of car here is interesting in that only one set of wheels are double flanged. This is always the outside set of wheels, riding on the rail which does not break. The design allows the cars to make use of the "switching" system without need of actual pointwork; while at the same time pass over the running cable for the second car.

The low wires

As noted earlier in a related post, the wires down near the rails are for the motorman's telephone.

Dead Weight Balance

Science Abstracts, Royal Soc. of London, 1899.

Electric Railways of Springfield and Holyoke, Mass.

(Street Rly. Journ. 14. pp. 415-423, 1898.)

The Mount Tom mountain-line, which rises 700 ft. in 4,900 ft., with a maximum grade of 21½ per cent., is worked by two cars connected by a 1¼ in. cable over an 8 ft. return sheave at the upper end of the line. There are no winding engines to drive the cable, but each car is equipped with two G.E. 1,000 motors, the cable being used only to balance the dead weight in the cars.

It's unusual

but it appears to be an electric system with an auxiliary cable. The driver has his left hand on an early "K" series controller, which you wouldn't find on a cable car. The trolley wire hardware is also typical of a 600v electrification scheme, rather than simply for auxiliary power.

I see why the car has two sets of wheels - so it can negotiate the cable crossings in the passing loop, but I suspect they're only on the side closest to the camera. I'd assume the other car has them on the other side. The passing loops were most likely biased so that the cars always ran on one side only, which would also explain the twin trolley wire.

Hybrid cars

It looks like it is electrically powered through the bypass area but otherwise a cable system.

Cable car

I think it is a cable car, on an incline. The two cars counterbalance each other. The trolley pole probably is for lighting. Of bigger concern, if you look at the wheels, it appears to be derailed. Might be an illusion, but it sure looks like it is on the ties on the right side.

[The car has two sets of wheels -- inboard and outboard. - Dave]

Mechanically inclined

Maybe a traction fan can help me with my confusion here. We can see the trolley pole deployed, and we can see bonding wires running around the fishplate right in front of the car, so at first glance this looks like an electric system.

At second glance there are rollers immediately in front of the car and that middle cable looks like it's been gripped cable car style.

Is this some sort of mixed system with cable assist on the steep grades, or is it a cable system with auxiliary power for lights etc.?

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