|Preliminary rendering of new
Hillsdale station with island platform
Vertical circulation to this island platform is provided at the north end (two stairways connecting to the sidewalks on each side of the new 28th Ave underpass) and the south end of the station (a new pedestrian tunnel with one stairway and one wheelchair ramp). In cross section, the new Hillsdale might look like this:
Of course, the accelerated schedule for its completion is closely linked to electrification, so quite soon thereafter it might look like this, with mixed diesel and EMU service. Note that per Caltrain plans, the overhead contact system is 22 feet above the rails. plenty to clear even the tallest freight cars.
Rebuilding Hillsdale Once and for All
There's a much better way to build the New Hillsdale once and for all. It initially looks like this:
tallest that have historically been used in this part of the corridor. Therefore, there is no constraint to freight service. This electrification will never change, with all the portals in their final configuration.
When all the diesels are gone and it's time to transition to level boarding, a track maintenance project takes place over a weekend. 43 inches of ballast are removed from under the tracks, using standard track maintenance machines. The rails are never even disconnected. (Not to be too flippant, this is still a major track maintenance operation that would require sophisticated planning and modern high-capacity machinery; but it is certainly within the realm of what Caltrain has done before.) Minor lateral adjustments are made to track and overhead contact system alignment, yielding this for the Monday morning rush:
That FSSF Thing
Placing the express overtake tracks on the outside, in a fast-slow-slow-fast or FSSF configuration, as opposed to the traditional slow-fast-fast-slow or SFFS configuration inspired by road design, is a key architectural decision for the blended system. The forces of traditionalism will argue strongly for SFFS because that's how it's "always" done, yielding nice straight express tracks down the middle of the corridor-- but clear exceptions to this "rule" exist, with examples of FSSF corridors in these videos from Sweden (with 125 mph express trains!) and Australia.
The fatal operational flaw of traditional SFFS corridors is that when a track must be taken out of service, either accidentally or intentionally for maintenance, commuter trains either must cut across the express tracks (fouling express traffic) to reach the opposite platform, or use super awkward bridge plates to board from the fouled express track. In contrast, an FSSF island platform is operationally flexible: the train simply crosses over to the opposite side of the island, without ever getting in the way of express traffic. For the peninsula "blended system" where Caltrain and HSR share the corridor, the operational headaches of SFFS could prove unworkable in the long run as the rail corridor is maintained.
One argument systematically trotted out against FSSF is this: wowing express trains around the outside of every island platform will make for a slalom "barf ride" that will give HSR passengers motion sickness, if not downright whiplash. This argument intuitively rings true, but turns out to be patently false when you run the numbers. In reality, an express train blasting around the Hillsdale island platform at 125 mph will do so on curves with a radius greater than four miles, requiring just 2 inches of superelevation to be rendered imperceptible to passengers.
|Download FSSF island platform plans
for every station on the Caltrain corridor
(3.3 MB PDF, see page 9 for Hillsdale)
- DON'T rebuilt infrastructure multiple times.
- DO build it once and build it right, in its final configuration
- DON'T build station platforms that are not compatible with level boarding, where this can be avoided.
- DO create the Caltrain engineering standards for level boarding.
- DO build the new Hillsdale station with a level boarding platform, years before the transition to level boarding occurs, by temporarily raising the track bed to make the platform only 8" tall.
- DO build the new Hillsdale station as an island platform, even after high-speed overtake tracks are added
- DO put the high speed tracks on the outside, in the FSSF configuration, for operational flexibility.