Rubber Tired Subways

Hi All,

Some time ago, I used the Montreal Subway system. It runs on rubber tires. It uses normal steel wheels on the inside of the tires as a normal train, but the weight of the car is on the rubber tires. Excellent ride, smooth and comfortable. Anyone every ride it, or one like it somewhere else? I believe the subway cars are built in France.

Never been to Montreal; but I have been on the Paris system once. It is interesting how they keep the steel-wheel/steel-rail system in place as a redundancy and safety measure; if any tire has a blowout, the steel wheels take the weight and traction is maintained. The tires run on a set of "outer rails" made of either concrete or some other material; the flanges of the inner steel wheels do the steering/guiding, not to mention the braking.

The Wikipedia article on this subject seems to be free of vandalism (thankfully); it does have a list of other cities that use this technology.

Hi Alan,

I was pretty much certain that the Paris subway was the template for the Montreal subway system. However I wonder whether the stations are as clean as the ones in Montreal. So far, the cleanest and most interesting subway stations I have seen were in Los Angeles, at the Red Line system. My favorite is the themed Hollywood station, with all of its movie film reels and movie cameras.

I automatically assumed that the tractive effort and braking were strictly assigned to the rubber tires, with the steel wheels as back up. The rubber tires have a much higher coefficient of friction and much higher braking power. Much larger footprint on each tire compared to the footprint of a steel wheel.

Mexico City's subway has the the same set-up as Paris, although I don't know if they have steel wheel back-up for flats. Equipment when I was there was French-made.

Hi Sumner,

How about slipping across the border and taking a ride on the Mexico DF subway and giving us a full report ??? Would be interesting to compare the three, so far, rubber tired subways for cleanliness, smoothness of ride, and comfort. And of course how you are treated. I assume your Spanish is up to snuff, although in California, when you slip across the border into TJ your greenbacks do all your talking for you. (TJ= Tijuana)

In 1967 and later, I roamed the Montreal system, about 1982 Mexico City and at times Paris. So much has been written about these systems that I'll just give a few impressions. Route 14 in Paris, the Meteor, is cabless with a wide railfans' window and forward-facing seats. Route 14 has platform doors, as JFK Airtrain. There is no on-board staff. As with some new trains on Route 1, the cars are "boa" style, without partitions between cars, though not articulated. About half of Paris' Metro is steel wheeled, with no plans to change.
Montreal's was built in preparation for Expo 67. From what I understand, all stations are perfectly straight, as the doors are observed from a position at one end of the nine-car trains. I believe all revenue mileage is underground, away from snow.
Mexico City's cars are more boxy. As in Montreal, the narrow cars require longer trains for the crowds. We were doing speed in the median of a freeway when a sudden downpour hit. The braking was excellent. A more recent route or two is steel-wheeled.
I see this problem: the weight of the extra wheels (including horizontal guiders) militates against passenger capacity.
Besides, some steel wheel systems have been designed so well that noise is minimal. Here on Long Island, the M7's not only have flat wheels, but the undercarriage components seem to rattle. The sound under the Bellmore trestle deafens.

Hi,

Believe it or not, I still have my Chevy Nova, bought in 1976 in beautiful downtown Seaford, right on Sunrise Highway. Still runs like a top. California weather certainly agrees with cars built for use on Long Island.

Interesting to note your experiences with all three systems. The part that peaked my interest was your statement that steel wheels, ie normal type subway cars are also in evidence there and doing quite well. It also appears that you are telling us that rubber tired subways do not age well. Wear and tear shortens their life span faster than straight steel wheels.

Assuming that all the rubber tired subways you saw, and rode in, are of French construction, that might just have something to do with it. Planned obsolescence. Got to keep those Frenchmen working. Appears that for rubber tired subways, the French have no competition.

(Yes, Pennsy, Bast Chevrolet is still in business, facing the Montauk Division parade of M7's and Speonk trains.)

Sorry, but I don't know the durability of steel wheel vs rubber tires on the three systems. I am quite certain that the French have a monopoly on design and bragging rights. Montreal chose the Parisian design in an era of increased ties between Quebec and De Gaulle. Mexico City's system has Paris as model, but also its first large transfer station resembled the big original one in Montreal. Part of Montreal's design was to avoid the viewless correspondence passageways of Paris. At Berri-Uqam, one may easily see in one glance the two major routes crossing (of three), one on a bridge above the other. In Mexico City, the transfer at Pino Suarez closely resembles Berri-Uqam in Montreal.
Unless I am mistaken, about five years ago the French firms were boasting that they had designed a rubber-tired Metro for Santiago, Chile.
Some place I have read a discussion on why six or so Paris routes have not been converted to rubber.
Joe McMahon

Yo Joe,

Would you believe I had to run outside onto the driveway to look at the rear of the Nova to confirm that the Chevvy dealer was indeed Bast ? Great car, and as I remember it, good bunch of fellas there.

From a Materials viewpoint, the steel wheels will outlast the rubber tires, several times over. The steel wheels will not flex, while the rubber tires will, and of course, that will heat them up, another problem.

On the positive side, better traction, bigger footprint for application of tractive effort and higher coeficient of friction. If necessary, the rubber tires could get the train up a steeper hill without slipping. However, where would you get a steep hill in a subway ??

pennsy wrote:where would you get a steep hill in a subway ??

In Montreal . Because of the use of rubber tires on the system, many of the stations were purposely designed such that the platform track was built significantly higher than the approaching track. This provided for greater acceleration out of and deceleration into the station.

Something else that hasn't yet been mentioned is the smell of "burning rubber" that pervades such a system.

Alan,
My memories sometimes gets mixed up over the decades. However, when you write of the heat built up in the tires, I recall that Montreal had unexpected heat in the Metro tunnels during the summer. The system, being up north, did not have air-conditioning. They had not factored in the heat built up in the tunnels by flexing tires.

In 1971, there was a blazing fire at the northern end of the line. One of the components after the crash was nitrogen in the tires.
Link: here
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Hills in subways? As well explained by Ken, because Montreal's metro was planned for the better traction of rubber tires, the straight run north to Henri Bourassa had deep bored tubes between stations, then hills entering each station. The expense of station elevators or escalators was thereby lessened. By avoiding cut-and-cover between stations, metro construction caused less havoc along Rue Berri (?) than cut-and-cover causes. A somewhat similar use of hills approaching stations can be found on New York's Interborough Subway, where on the circa-1905 Broadway line, the stations at 157th, 168th, and 181st Street have slopes at either end. Both on the Interborough (c. 1905) and in Montreal, this profile assists braking entering the station and acceleration leaving stations. The hills in Montreal Metro Ligne 1 are much steeper than under upper Broadway, Manhattan.

(This talk of Montreal is a memory of pleasant trips. In 1953, Dad brought us out the busy St-Denis streetcar line to Ahuntsic, which route was later paralleled by said Metro route. Fourteen years later, I led fifty weary Staten Island high schoolers through the new Metro to Expo 67.)
Joe

Ken V wrote:Because of the use of rubber tires on the system, many of the stations were purposely designed such that the platform track was built significantly higher than the approaching track

How steep of grades are we talking here…? It's not unusual to see grades of between 4 and 5 percent on the NYC subway (even steeper), as far as steel-wheel traction goes; the ceiling for LRT is perhaps in the 9 percent range; and of course, Shays and Climaxes go into the double-digits insofar as what they can climb.

The Wikipedia article states the grades can be up to 6½%. My memory makes me think some were greater than that, but the mind does play tricks.

Hi All,

Fascinating article on the Montreal fire. The nitrogen in the tires would help put out the fire, but would mandate that the firefighters have breathing equipment.

The smell of the hot rubber in the stations most probably would be offensive, especially to the ladies of French Canadian descent. After all the money they spent on their exotic French perfumes, the smell of hot rubber tires would really set them off. And their gentlemen friends would probably feel the same way. Bad news.

I am rather surprised to learn that gradients as large as 6 % are in subways. One usually expects a gentle rise in the track and a clear view down the length of the train until you take a sharp curve. As far as I can remember, the steepest climb in a subway I ever experienced was with the IRT, Brooklyn, Interborough Rapid Transit, coming out of the tunnel at Utica Ave. heading towards Sutter Ave, elevated. That was a decent climb. Only in the dead of winter was it a problem.

This article from the Montreal Gazette of September 14, 2005, by Roberto Rocha may be of interest. This analysis favors steel wheels because of recent improvements in steel wheels and suspension.

It says that the steepest grade on the Montreal Metro is 6.5% at Verdun station. The article also says that Santiago's newest route is steel, not rubber as earlier routes.

As a New Yorker, I wonder where our steepest grade is. I would not be surprised if it is in an East River tunnel. By the way, the Sixth Avenue Express tracks from West 4th to 34th Streets, bored under the H&M about forty years ago, are an example of dropping down between stations to save construction costs. One side-effect is that there is no express station at Sixth Avenue and 14th Street.
Joe