Saturday, November 22, 2008

BART Rumor Mill

There was a post up on Daily Kos today heralding the passing of BART to San Jose. Lot's of folks have different opinions about it but I was wondering if what one of the commenters said was true. I had never heard of this but commenter Maynard Krebs stated this:
When San Mateo County dropped out of BART expected revenue was too low to support BART to Marin. So the Marin line was dropped too but the 5'6" gauge was designed to be stable while crossing the bridge in high winds.
Does anyone know if there is any truth to this high winds theory? I had always heard it was just to make people comfortable by allowing wider cars by crazed futura engineers. I often wondered how they would deal with winds on the bridge.


Loren said...

A broader gauge makes for greater stability, because the center of gravity can be lower in both height above the track and angle relative to the rails. But I've seen another theory posted in a Usenet message (, etc.):

That the broad gauge was to keep BART trains from running in the Southern Pacific Railroad's tracks. That railroad had most of the available trackage in the Bay Area, and it might be logical to run BART trains in that trackage. So the Southern Pacific did not want to be saddled with more passenger trains, which had not exactly been moneymakers. BART's planners decided to keep the SP's management from complaining by making their trains incompatible with SP's tracks, so that extra construction will be necessary.

That aside, I'd asked in the Usenet newsgroup ba.transportation about "Nine-County BART Map?" -- some early plans for BART.

1961 BART proposal was the originally-constructed system with two extra lines: Daly City to Millbrae to Palo Alto, and downtown SF to the Golden Gate Bridge to Santa Venetia in Marin County. But Marin and San Mateo Counties pulled out of the BART district, and Contra Costa County almost did so.

Nine-County BART is a somewhat schematic map of BART's routing as planned in the late 1950's. It went to Los Santa Rosa, Napa, Fairfield, Antioch, Livermore, and Los Gatos. The two SF-Marin routes in it were two alternate possibilities.

I've located the original 9-county map; it is in the book "Regional rapid transit, a report to the San Francisco Bay Area Rapid Transit Commission, 1953-1955" published by Parsons Brinckerhoff in 1955, and available in the MTC-ABAG Library near the Lake Merritt BART station. I would be most grateful if someone would photocopy the proposed map from there and scan it and put it online, since I no longer live anywhere close to the Bay Area, and I'm not likely to afford traveling there anytime soon.

arcady said...

BART cars are 10.5 feet wide, which is about the same width as mainline commuter trains in the US, so the track gauge has nothing to do with train width. I think it has more to do with the system being designed by engineers with no railway experience, so they had to do everything their own way, hence the non-standard gauge and voltage, and the fancy (and initially rather unreliable) computer control system, which provided nothing that the Key's system couldn't do if the trains were fitted for automatic driving.

Anonymous said...

Things would have been so much easier if the Key System were not trashed.

Steve said...

I have a copy of Interurbans Special 31 - BART at Midpoint by Harre W. Demoro. According to the timetable in the book, the Golden Gate Bridge & Highway District in September of 1961 refused to allow trains on the Golden Gate Bridge. San Mateo County rejected the BART plan in December of 1961.

System design was handled by Parson Brickenhoff and started in June of 1965, long after Marin County left the BART District so stability on the bridge would have nothing to do with the BART car design and gauge used.

Parson Brickenhoff were the ones who recommended the 5' 6" gauge in a report regarding the stability of lightweight trains at high speeds. "It is recommended that the BART system vehicle and track system be designed to a gauge of 5' 6". Findings clearly indicate that this approach would assure the lateral stability and safety of the desired lightweight vehicle more effectively and economically than any other design approach." The tests were performed with models in wind tunnels.

Hope this helps.

Anonymous said...

Parsons, Brinckerhoff is the company started by the Parsons who designed the first subway line in NYC.
Bechtel Corp was both a member of the consortium oberseeing BART engineering/construction and represented on Southern Pacific's BOD by S. D Chair and Jr. as member.
At the time these decisions were made the speed record for rapid transit trains 76 and change was held by Chicago Transit Authority set with hot rodded PCC based cars on 4'8 1/2" guage track.

serial catowner said...

Sometimes a cigar is just a cigar. The BART system was intended to be built over a period of 50-75 years and be the backbone of commuter transportation in the Bay area for over a century. Planning started before 1949- I've read a book from 1949 summarizing the planning to date (at that time) to build an all new Bay area commuter system.

Without getting too deep in the weeds here, what happened is simple- it's very difficult to go to a wider gauge in the future, the planners thought a wider gauge would be a logical future choice, and they believed BART was big enough to ignore the grandfathered 'standard' gauge of the existing rail lines.

After all, it's not as though nobody had ever asked this question before- India, Russia, Australia, England, and the American south all had at one time a large broad gauge network.

arcady said...

These days, there are 3'6" gauge trains that run at 100 mph, and standard gauge trains that run at 200 mph. Meanwhile, I don't think Indian Railways has any trains that even hit 100 on broad gauge. So track gauge is far less important than people tended to assume, and standardization is by far the most important aspect of it. Maybe they didn't realize that in 1949.

295bus said...

Every couple of years I read someone authoritatively stating "the" reason for BART's 5"6' gauge. None of them really make sense. I think the main reason BART eschewed standard gauge was "not invented here".

Darrell said...

I remember hearing in the latter 1960s that BART's wide gauge was for stability in the windy Bay Area, as detailed by Steve's comment.

Whether technically true or not, it was a publicly-stated reason.

Eric Fischer said...

The BART "Rapid Transit" newsletter when the wide-gauge decision was made (February-June 1964) said that "exhaustive study shows the wide gauge will provide greater stability and smoother riding qualities for the District's high speed rapid transit trains. ... The recommendation was based largely upon the findings of wind tunnel tests conducted by the Stanford Research Institute. According to the tests, a wide gauge will be most suitable for the combination of circumstances which exist in the Bay Area -- the high speeds and light train weights, together with the prevalent high winds." The decision can't have been connected with the Golden Gate Bridge because Marin had already dropped out of the district in 1961.

Loren, if you are still looking for the overview map from Regional Rapid Transit, here it is:

Roland Lawrence said...

Interesting reading have to say. Being in the UK I can only envy the wide and spacious train sets on the BART system. Here in the UK every corner was cut for the London Underground expansion. The effect is that the trains have 1/2 that of the sets used on the BART system. You would think the amount saved to be huge. However it transpired to be around 10-12%. Most of the cost of the railway is the purchase of land, building stations and other infrastructure. A few extra feet of ballast costs are minimal.

Broad gauge cars are more stable, in freight terms allow double stacking of containers inside the frame (lower overall height), have a more stable ballast - lower maintenance costs.

The rough ride comes from wheel creep, however the new cars for the BART system have independent running wheels. Once running should be smooth as...