TrainBlog by Marcel Marchon

San Francisco’s Third Street Light Rail Line - to be known as the ‘T’ line - opened for limited (free!) weekend service today. Regular all-week service will commence on April 7 of this year.

Service begins at 10 a.m. and continues until 7 p.m. For the first three months, the T-Third will operate only on weekends between 10 a.m. and 7 p.m. Anyone who boards a train south of Fourth and King streets can ride the line for free until April 7, when full service is scheduled to start.

[Quoted from SAN FRANCISCO / Muni’s Third St. light-rail line finally rolling ]

The Third Street Light Rail Line runs southwards on Third Street from the current terminus at Fourth and Kind Streets (next to the Caltrain station) and terminates near the Bayshore Caltrain station. (at Bayshore Blvs. and Sunnydale Ave.) I think, originally there was supposed to be a station right next to the Caltrain station, but for some reason, this was not implemented.

The T line will continue northwards along the Embarcadero trackage and into the Market Street tunnel to its northern terminus at Castro station.

Effective April 7, 2007, the N-Judah line will stop serving the 4th & King station and now terminate at Embarcadero station. The J-Church line will provide peak hour only service to 4th & King.

I’ve long been fascinated by urban subway/metro/underground rail systems (in my youth, I was a big fan of the Paris Metro) and lately, I’ve been watching a couple of British Rail DVDs - one of them is focused on the London Underground Metropolitan line. Here’s a couple of interesting bits of information, that I learned while watching this DVD and from subsequent reading on related web sites:

• The London Underground network reaches out into some quite rural country - one example of this is the Metropolitan line (which incidentally was originally built as a mainline railroad), which even has a single track branch. In the video, you can see the train threading through heavily wooded areas on the Chesham branch … Parts of the Metropolitan line were steam powered until the second half of the 20th century and reached even further out into rural country.
• The London Underground is electrified using a 4-rail DC system. This is quite rare and differs from the more common 3rd rail system by having a fourth center rail between the two running rails. The voltage used is 630 V DC, with the outside (3rd) rail at +420 V and the middle (4th) rail at -210 V. In some cases, where tracks are shared with regular mainline trains that use rolling stock equipped for the more conventional 3rd rail system, the outside rail will be at +630 V and the middle rail at 0 V - the difference in potential between the two rails is the same either way and the trains will work just fine.

Another peculiarity of London Underground and suburban railroading is that in some locations, you can find tracks electrified using the 3- and/or 4-rail DC system running next to tracks electrified with overhead catenary at 25 kV AC. One example of this is on the tracks out of Euston station on the West Coast Main Line.