At last week’s Palo Alto Rail Committee meeting, Marian Lee, head of Caltrain’s modernization program, presented an update on Caltrain’s analysis about where passing tracks might go in the blended system where Caltrain shares tracks with High Speed Rail.

This is long term planning – passing tracks would be needed at – or after – the time that high speed rail first arrives on the Peninsula. If the High Speed Rail project is on schedule, without delays in funding or construction, the soonest it would get to the Peninsula is 2029, and the current tracks can carry up to 2 high speed trains per hour without any passing tracks.

Caltrain is analyzing 5 different locations, 4 with 4 tracks and one with 3 tracks. There is a northern option, from Bayshore to Millbrae, a 9 mile “full midline”, from Hayward Park to Redwood City, a 6 mile midline, from Hayward Park to Whipple, an 8 mile southern option from San Antonio to Lawrence, and a 16 mile 3-track option from Hayward Park to Cal Ave.

For in-depth discussion of passing tracks, and an interactive tool you can use to analyze options yourself, see <a href=”http://caltrain-hsr.blogspot.com/2011/05/where-four-tracks-will-be-needed.html”>Clem Tillier’s blog</a>.

Caltrain’s initial analysis shows that the best technical performance comes from the “full midline” option, and the next two are the short midline and southern options.  Lee said that Caltrain’s operation staff was very leery of the 3-track option, which would have trains using the track in both directions. In theory, the “positive train control” system would prevent collisions by automatically stopping the trains.

The complete analysis will consider operations, engineering and construction, right of way requirements, cost, and city/county approval.

While the passing track scenario is longer term, a decision about the location of future passing tracks will help cities make reasonable assumptions about land use along the corridor.  For example, in the discussion about a planned “Transit Village” development in San Carlos, some residents have raised questions about whether the development conflicts with future requirements for passing tracks.  With these questions answered, communities will be able to make confident land use decisions.