Alternatives Analysis Analysis, Part 1

This post is the first in an open-ended series, picking through the recently-released preliminary alternatives analysis. The AA is a voluminous document with plenty of material to be dissected over the next several months, in no particular order.

The Station Access Fallacy

Section 4.1.2 of the Alternatives Analysis discusses track and station arrangement options. In particular, it is pointed out that a key consideration in providing good station access for Caltrain passengers is to consider that the majority of Caltrain stations, and the majority of Caltrain ridership, is on the west side of the tracks. That sounds pretty good in theory... but in practice, consider the following:

• The rail corridor must be 100% grade-separated, with no crossings, so passengers may only cross the tracks via pedestrian underpasses or overpasses, never at grade.
  
• To access an island platform, or the platform on the "far" side of the tracks for at least one direction of a passenger's daily commute, every passenger will use underpasses or overpasses at least twice daily regardless of station configuration, and regardless of which side of the tracks they might live or work.
  
• Putting Caltrain on the west side of the corridor, rather than in the middle, might save each passenger a grand total of 30 feet of walking distance, far shorter than the stairs or ramps to the platform or the walk to the doors of an 85-foot rail car.
• It takes seven seconds to walk an extra 30 feet. Some hike!
  

In a 100% grade-separated corridor, it is given that station access will be limited to a handful of access points somewhere along the 800-foot length of a Caltrain platform. As long as those are well-planned (e.g. Belmont), that's perfectly acceptable. The station access "advantage" of putting Caltrain on the west side of the corridor is insignificant.

The One Percent Rule

In the AA profile plans of Appendix B, page 3, a design criterion is established: the maximum grade for Caltrain (shared use) tracks with diesel-powered freight trains is 1.0 %. The community impacts of this gentle grade, required exclusively for freight trains, were previously discussed. And yet, Caltrain's own engineering standards state that "maximum design gradient (...) for grades up to two (2)% may be implemented with the approval of the Caltrain Deputy Director of Engineering. (...) Grades exceeding one (1)% shall be limited to tangent length less than 1200 feet." Why is a more stringent standard now being applied? Certainly not for high-speed rail or Caltrain, both of which will easily handle 3% grades.

The results of this conservatism are already apparent. For example, the proposed elevated alignment through downtown San Mateo would require lowering 1st, 2nd, 3rd, 4th, 5th and 9th avenues, with extreme community impact, because (a) the grade is 0.8%, even less than the specification, and (b) there is a requirement to return to grade level before the curve into Hayward Park to avoid having a vertical curve in a horizontal spiral, a track geometry complication exceptionally allowed for (see TM 2.1.2 paragraph 6.1.7) in the CHSRA's own track design guidelines. Let's face it: the age of picks and shovels is over; in the 21st century, computers, lasers and differential GPS should make the construction and maintenance of overlapping vertical and horizontal curves a breeze, without having to demolish half of downtown San Mateo.

With things already tight as they are, the time for making judicious and appropriate design exceptions is now. Using overly-generous specifications will unnecessarily constrict the design space, inflame community opposition, and drive costs through the roof.