Paul sent me a link to How to Make Public Transit More Appealing
In the Bay Area there is a pretty reasonable system of public transit which consists of several independently operated, yet inter-connected, systems. These systems consist of trains, busses, electric bus lines, a high-speed rubber on concrete rail-type of thing (BART), and a subway in San Francisco. They connect the Bay Area nearly completely, effectively connecting each city that comprises the Bay Area. Despite the connectivity public transit is (in general) not a feasible means of travel because it can take a prohibitively long time to travel between two points. The problem is exacerbated by the independence of each system, they are pretty well coordinated, but there is always a small layover when changing systems. Let’s look at an example: traveling from where I am staying to the San Francisco Airport.
To make this trip I will board the Caltrain in Mountain View, the station is less than a mile from my residence so walking is not a problem. I will ride northbound until I reach the Millbrae Station where I will transfer to the BART which I will ride to San Bruno, and change trams to finally reach SFO. By all rights this is a pretty easy system to use, only changing rides twice during the 25 mile journey. The problem is that it will take nearly an hour and a half to make the trip (with transfer times). The longest leg of the journey is on Caltrain, it is 24 miles, and it could take up to 50 minutes. The reason that it could take so long is not that the train is slow—it moves at a respectable pace—but that there are 11 stops to make along the way. There are morning and evening commuter runs that skip most of the stops cutting the transit time to just under 30 minutes, so options are available to speed up the trip, but in general there will be a great deal of time wasted stopping and starting.
The long trip duration generally makes public transit a less attractive option than driving.
Presently plans are in the works to build a high speed rail (~200MPH!) connecting all of California with a primary line between Los Angeles and Sacramento, and I can’t help but think that—despite the speeds—the trips could still take quite a long time because of all the stops. Reducing the number of stops would make the trip faster and therefore better, but it reduces connectivity and thus would make the system overall less appealing for the taxpayer who is paying for the initial investment. It is possible to run a skip-stop schedule, wherein certain stops are skipped at certain parts of the day, but that makes the schedule complicated and limits the robustness of the system.
The solution to this problem is not to skip stops, but instead to prevent everybody from stopping at every stop. Instead of making the entire train stop at every station, let a specified number of cars stop. Imagine the following scenario: There is a train line running between Houston and San Antonio1, along the route it passes through College Station and Austin (~300 miles). The train leaves Houston with six cars and a primary engine, as the train approaches College Station the last car will separate and switch onto a deceleration track that intersects with the station. Somewhat before this a single car will depart from the College Station station on an acceleration track which will intersect with the main track. The car that left College Station will become the lead car of the main train. Likewise, as the train nears Austin two cars will separate and enter a deceleration track. Only those passengers who wish to debark need to stop, the rest of the train can keep a-rolling on down to San Antone’.2,3
This method of operation alleviates several problems other than wasted passenger time. First it saves energy since most of the train is not stopping and starting. Second it will reduce congestion and confusion in each station, all the people who are departing will be on a train car before the people arriving from Houston even enter the station. The system will remove the need for stop-skipping and therefore reduce the number of trains that will need to be run per day. Each car will be parked at a station for some period of time during the day, and thus can easily be cleaned by a janitorial crew without having to work at night or inconvenience any travelers. Also, the train at large will not need to pass through each city along the way, thus the primary route can be optimized. Further, adding stops to the trip could be done without requiring a significant change to the overall infrastructure.
With proper engineering the cars themselves can be completely passive (with the exception of a fail-safe braking system), the track can slow the car and collect the energy of stopping with some regenerative system, that energy can then be used for accelerating the next car that will depart. A certain amount of energy will (of course) need to be added to the system to account for inefficiencies, but overall energy will be conserved. Along the primary route the engine will be able to maintain a relatively constant speed and thus its operation can be optimized as well.
This system will have its difficulties in timing and general execution, but it seems that the benefits could out-weigh the challenges. The scale of the system is really not a concern, meaning that a similar tactic could be used for area-wide transit at lower speeds so long as people have sufficient time to travel between cars to make their stop.
I welcome your comments and criticisms of the proposed.
Notes:
- I’m going to use Texas because more of my readers know the geography of Texas than California.
- Travelling at 200mph by train the trip from Houston to San Antonio would take a little over one and a half hours (accounting for acceleration and deceleration) even with the ‘stops’ in College Station and Austin, by car on I-10 the same trip would easily take an hour more than that.
- I bet there’s rich folks eating in a fancy dining car!
