The following fairly simple argument shows why Hillsdale
is the only feasible overtake location on the Caltrain line,
and why Caltrain's major civil works should be
focussed very, very stringly around (possible phased) of
construction a mid-line amplification around a four-track,
two-island-platform Hillsdale station.
The final suggested operations pattern/infrastructure I
describe below is shown in this
My starting assumptions are always that:
- Clockface schedule is non-negotiable.
30 minute period should be the baseline, given billions
invested to be in the line; 15 is aspirational; 20 is
possibly an intermediate stage (20 peaks, 30 off-peak,
though it results in BART-like messy irregularity.)
Caltrain planning should aspire to an 18-hour-a-day
7-day-a-week base service level that frees its customers from
complex timetable consultations and that facilitiates
reliable and regular connecting feeder bus
services at any station.
- A minimum number of simple stopping patterns is key.
Apparently arbitrary messes (like today's Caltrain
clever-but-flawed compromise-of-necessity) actively confuse
and repel potential riders, and larger than 30 minute
headways for stopping patterns are simply unacceptable.
- There are two classes of stations: major and minor.
All regular expresses stop at all major stations.
All local trains stop at all minor stations.
Caltrain is not a large enough or varied enough system to
require or support significantly more complexity than this
(with the possible exception of supplemental
- Same-direction stationary overtakes of locals by
expresses while both are stopped at major stations, using
cross-platform transfers to effect minimum-time
station-to-station trip times for a rich selection of O+D
pairs, is the most desirable base scheduling solution for
Caltrain, given the above.
In essence, most of the above points reduce to "if it's good
enough for the Dutch and the Swiss and the Germans it's good
enough for me", or, "copy what has been shown to work", or,
"emulate, don't innovate".
Timetables should be memorized ("express at 17 and 47 past the
hour, every hour"), not carried around and constantly
consulted. Deciding whether to board a train should be a trivial
yes/no decision ("is my station served by express trains or only
local trains?"), not an error-prone and intimidating
Slight variations to strict service pattern regularity are
possible in special cases. Adding 22nd Street stops for
expresses in one direction only in AM/PM is the only one that
springs to mind.
Supplemental peak trains in addition to the clockface
might have customized stops (driven either by market demand,
infrastructure inadequacies or a combination), but the base
service regularity is non-negotiable.
Again, if it works for the people for whom things demonstrably
work, it's good enough for me.
With only two train types, both operating predictably and
regularly, we can provide scores of competitive trip times,
without operating a mess of different customized train patterns.
This is simple, it's clear to riders, it's easy to operate,
and it's much more efficient to operate (more people served
better by fewer trains, combined with "good" trains for a given
O+D operating minimum every 30 minutes rather than every hour
for today's ad hoc collection of stopping patterns = better
loadings = better revenue/cost.) It's also pretty clever.
Lastly, people already know how to change trains at MacArthur
station on clockface-scheduled BART with zero time penalty and
near-100% reliability, one is not attempting to impose something
foreign or suspiciously newfangled on the Sophisticated Bay
Area Transit System.
OK! So those are the assumptions. I've never seen anything to
indicate they're not the right ones!
So, building on that, the Major Stops are -- and I think this is
pretty non-controversial, especially since we're guaranteeing far
better service to all stations, including Burlingame and
Belmont, with this plan:
- MISSION BAY (aka Fourth and Townsend, aka Fourth and King)
- MILLBRAE (for political, not "intermodal" or ridership reasons)
- HILLSDALE (for logistical reasons)
- REDWOOD CITY
- PALO ALTO
- MOUNTAIN VIEW
- SAN JOSE
The overall major/minor stop pattern is:
||4 intermediate local stops
|South San Francisco
|(Broadway, within sight of Burlingame, closed)
||2 intermediate local stops
|(Hayward Park, within sight of new Hillsdale, closed)
||2 intermediate local stops
|(Atherton, of no utility, closed)
||1 intermediate local stop
||2 intermediate local stops
||3 intermediate local stops
So, here's the simple argument, at last!
It comes down to this simple table, explained more below:
Now I claim we can model the run-time penalty for making a
local stop versus running through a station as an express
acceptably accurately as a constant per stop, given Caltrain's
comparatively flat and comparatively straight route, and
assuming station spacing of 1.5 miles or better. This penalty
is somewhere around 2.0 minutes at present, and should decrease
to somewhere around 1.5 minutes in the future under even
unambitious operations/rolling stock/platform improvement
scenarios. (1ms-2 braking/acceleration = 2.2mph and
a top speed of 35ms-1 = 78mph, combined with 30
second dwells, both easy goals, gives a 60 second penalty. So
we're can imagine being in the 90 second ballpark. The same
direct calculation with present-esque circa 0.5ms-2
"performance" and circa 1 minute dwells, pencils out correctly
at 110 seconds stop penalty.)
So let's sketch out what happens when different major stations are
chosen as the overtake location.
If, for example, Millbrae is the overtake station, then at the time
a southbound local starts to decelerate for San Bruno should be
1 stop penalty period ahead of the overtaking express; 2 penalty
periods ahead at South SF, 3 at Bayshore; 4 at 22nd Street; and
4 at Mission Bay (where the express also stops).
Heading past the overtake, by the time it slows for Hillsdale it
will be 2 penalty periods (corresponding to Burlingame and San
Mateo) behind the express. By the time it reaches San Jose it
will be 10 local penalty periods behind.
Putting this all together in tabular form, with entries
corresponding to penalty periods that an express ought to be
behind or ahead of a same-direction local train at a particular
stop, we arrive at the table above.
Now, to be realistic, given the Egregious Right-of-Way Sabotage
Campaign of the period 1992-1999, it is today quite infeasible to
construct express/local coordinated-overtake (four tracks, two
island platforms) at either Millbrae (ROW given away to BART) or
Mountain View (ROW given away to VTA) at any time in the
So let us consider only the three cases of Hillsdale, Redwood
City and Palo Alto from here on.
For a stop penalty of 1.5 minutes, the above translates to:
With such (optimistic) train performance, the above shows that no
additional scheduled express/local overtakes should take place on the
Caltrain line for local headways of greater than 10 minutes.
Buy high-performance trains and operate with a lot of discipline
(two corners of the famous Swiss
"rolling stock"/"service plan"/"infrastructure" Magic
Planning Triangle) and one need construct only one overtake location
line-wide, at a choice of one of three locations.
For a stop penalty of 2.0 minutes:
- This shows that if the coordinated local/express overtake
point were at Hillsdale, a southbound express would
catch up to a second local train (assuming 15 minute local
headway) one stop before San Jose, ie around Santa Clara. So
passing tracks would be necessary at that point. (Because of
the inherent symmetry of the service pattern, this also means
that a northbound express would pass a second local train
around the same point.)
Fortunately, such passing tracks are feasible to construct
around this point, and appear to be part of Caltrain's
No additional overtakes are scheduled north of Hillsdale,
so further extension of the existing short Bayshore quadruplication
is not necessary.
- If the local/express overtake were at Redwood City, an
overtake would occur one stop before Mission Bay, ie around 22nd
Street. This is an infeasible construction project, so a
timetable featuring 2 minute local station stop penalties, 15
minute local train headways, and coordindated overtakes at Redwood
City is not a candidate.
- If the local/express overtake were at Palo Alto, an
overtake would occur three stops before Mission Bay, ie around
South San Francisco.
Providing the amplification for this overtake is a feasible,
if expensive construction project, involving extension of existing
quadruple track from CP Brisbane, though South San Francisco and
San Bruno stations, as well as quadruplication around Palo Alto
(at least south past California Avenue, and ideally north also
across San Francisquito Creek and through Menlo Park.)
Extension of the Lawrence quadruplication would not be
necessary to provde this service pattern (in isolation).
For a stop penalty of 2.5 minutes:
- This shows that if the coordinated local/express overtake point
were at Hillsdale, additional overtakes of 15-minute local
service would take place around Bayshore and Sunnyvale.
- If the local/express overtake were at Redwood City,
additional 15-minute overtakes would take place around South
San Francisco and Santa Clara.
- If the local/express overtake were at Palo Alto, an
additional overtake would occur around San Bruno.
This shows that a 2.5 minute local stop penalty combined with
reasonably frequent service results in excessive capital costs (a
bad 1940s choice of "rolling stock" compromising the
"infrastructure" and "service plan" corners of the Magic
Planning Triangle.) I claim that it is self-defeating to make any
plans for significant expansion of Caltrain service or major
investment in Caltrain infrastructure under such a train
performance assumption -- the wasted cash involved would be
better spent building BART to Santa Barbara or something.
I claim that overall the Hillsdale overtake pattern is the
optimum realistic and feasible service pattern for the Caltrain
corridor, for the following reasons:
- A 2.0 minute local (minor) stop penalty is a realistic planning
and operations goal, allowing a great deal of recoverability,
especially when combined with higher-performance trains and level
- A timed-transfer cross-platform overtaking move near the
midpoint of the line results in the most rider-friendly
regular service pattern.
- Construction of a new and suitable Hillsdale station is already
a medium-term (or even near-term) Caltrain goal, is
supported by the host city, and appears in official city plans.
- Quadruplication to support this service pattern is only
necessary at locations
- associated with the coordinated overtake point (Hillsdale and
adjacent stations) itself; and
- as a second phase to support of 15-minute local service headway
at a location (CP Bowers to CP Coast) where is both fairly
technically simple to construct (wide right of way and
only three significant rail bridges), where there is little
lineside residential (NIMBY) development, and where it ties
in simply with existing and planned quadruplication at either
end of the necessary amplification to provide a usefully
long and flexible overtaking stretch (existing CP Hendy to
CP Bowers quaduple track linked to future CP Coast to
San Jose amplification by others.)
- Incremental extension of the extent of the quadruplication is
possible (to the south, placing the Downtown San Mateo Grade
Separation and Right of Way Sabotage Outcome Disaster in the
"too hard" basket for now) in a small number of steps which
are technically managable, operationally useful, and perhaps
even politically feasible:
- Quadruple Ninth Avenue/CP Palm (MP18.3) to Forty Second Avenue
underpass (MP21.0), constructing the already-planned new
four-track two-island Hillsdale Station;
- Quadruple MP21.0 to CP Ralston (MP21.6) (ideally combined with
first phase; this is technically separable, but at greater
- Triplicate south from CP Ralston by building an express track
on the east (southbound) side of the tracks around Belmont Station
from MP21.6 just north of San Carlos Sation MP21.0.
This involves no reconstruction of the new-ish Belmont station,
and should involve no or minimal ROW takes on the east side.
- As ridership builds (as it inevitably does based on predictable
and faster timetables), and the local train service interval is
decreased below 30 or 20 minutes, add express tracks south of
CP Bowers to meet with quadruple track at CP Coast
- At a much later date (the above infrastructure is adequate
to operate the service pattern with acceptable reliability),
complete quadruplication through Belmont, San Carlos and
Redwood City stations to Redwood Junction.
San Carlos would be reconfigured
as a single island platform station with the existing
eastern platform widened, the western platform abandoned,
and two new tracks (local and express) constructed to
the west of the existing ROW, in conjunction with planned
Transit Oriented Development and relocation of the historic
Redwood City station would be relocated to a location
between Brewter Avenue and Broadway (circa MP25.3) and
configured with two island platforms, with scope for
eventual expansion to full HSR (400m, 1300') platform
- Even though an ideal mid-point overtake would involve two or
more local stations both north and south of the major station
overtake point (providing more reliable on-the-fly catch-up
overtake approaching the major station and and pull-ahead
following it, and thus less likelihood of late lead trains
delaying followers), the choice of Hillsdale is an acceptable
service plan versus infrastructure compromise.
Slightly delaying northbound local departure from
the Hillsdale station platform (1 to 1.5 minutes) allows the
overtaking express to depart and start to clear (shorter,
closely-spaced) track blocks through two-track downtown San Mateo;
and scheduling southbound locals to arrive 2 minutes early and dwell
at Hillsdale awaiting the southbound express' cross-platform arrival
enables low-average-delay entry of the latter into the station.
Alternatives to this small (circa 2%) increase in
local train trip time include:
- Extending track amplification north of CP Palm through
San Mateo station, building many highly desirable grade
separations, though in a highly constrained ROW with
enormous construction and staging challenges
- Retaining a station at Hayward Park, and using the local
stop penalty it induces reduce scheduled extra dwell at
Hillsdale. However, given that the Hayward Park station
site is literally within sight of the proposed relocated
Hillsdale station's platforms (risking politically dangerous
analogy with Burlingame/Broadway) and that the capital costs
of building a centre-island (local tracks) station at Hayward
Park will be significant due to the need to build a pedestrian
underpass to reach the platform and due to the constrained
right-of-way width at that location, the compromise of
slightly delaying local trains at the Hillsdale station
while avoiding the capital costs of a Hayward Park station
seems to be the correct solution.
- Designating Redwood City as the overtake point,
and quadrupling from north of San Carlos to south of
Menlo Park -- a solution which may even superior
from a service planning perspective due to the potential
importance of the Redwood City station, but which involves
great political challenge (San Carlos station ripped up;
Atherton hysterics; much Menlo Park uncertertainty) beyond
the comparatively settled and approved situation at Hillsdale
and the opportunity for a comparatively low-impact
incremental triplication though Belmont station
- Abandoning the concept of regular interval service
and cross-platform, same-direction local/express overtakes.