All-express high-speed rail?

[Pragmatic Idealist]

I have a question.

Why aren’t shorter express trains with, perhaps, more automation and more spurs and sidings a feasible way to decrease travel times? Or, would such a modification work?

Is it possible to make high-speed rail more like personal rapid transit so that there is less deceleration and acceleration involved?

Maintaining constant speeds is so important for this mode that I question why the subject has not been addressed in the 50 years since high-speed rail was first introduced. The technology is seemingly there in order to make such an all-express system cost-effective.

[DetroitPlanner]

Coming from a City that has this, I can tell you it is expensive to build and operate and generates little return. Its great for major events, but otherwise it is underutilized. http://www.thepeoplemover.com/WE-LL-...HERE!.id.2.htm

[joshww81]

I have a question.

Why aren’t shorter express trains with, perhaps, more automation and more spurs and sidings a feasible way to decrease travel times? Or, would such a modification work?

Is it possible to make high-speed rail more like personal rapid transit so that there is less deceleration and acceleration involved?

Maintaining constant speeds is so important for this mode that I question why the subject has not been addressed in the 50 years since high-speed rail was first introduced. The technology is seemingly there in order to make such an all-express system cost-effective.

I had a railway engineering class today and the lecturer was keen to emphasize that the main aim of railway transport is to minimize any form of resistance so as to facilitate rail travel, particularly for high speed trains. The difficulty about trains is that, due to the large weight involved, a lot of energy is necessary to kickstart momentum and acceleration to push the train forward.

As such, for high-speed rails, they are, in engineering context, really only useful in combating resistance at high speeds (i.e. above 200+kph). For this to happen, the distance between stations must be adequate to allow for the speed to take place. It does not make sense to have them travel at maximum speed for 4.8 sec only to start deceleration into the next station. High speed rails also need special railway infrastructure equipment different from typical rails, e.g. need to go ballastless to hold the rails firmly down in place. If speeds fall below a certain optimum, it's much better to revert to conventional metro systems since they are more energy efficient.

In this regard, I don't think it's possible to treat high speed rails like personal transport. I guess this can be countered by supporting a high speed system with other standard rails/bus network planning.

My 2c worth.

[mgk920]

Agreed - the true high-speed passenger rail lines now being built all over China have trains that run non-stop between their major city terminals on entirely new purpose-built grades. For trains that run at 350 km/h (about 220 MPH for the Luddites in the crowd), these lines require, for example, a minimum curve radius of 7000 meters (about 4.5 miles). Non-stop express trains on their recently completed line between Guangshu and Wuhan cover a distance roughly equal to that between Chicago and Philadelphia non-stop with a schedule of about 3.5 hours from 'doors close' at one terminal and 'doors open' at the other.

These services aim at intercity traffic now using airlines.

That said, their new high-speed lines do have intermediate stations that are served by local and regional true high-speed trains. Their platforms front on short passing sidings that branch off of the lines' main tracks, allowing the trains running express/non-stop to safely blow through at full speed.

If you think that building the USA's interstate highway system was fun, especially in densely-developed urban areas, just try building these true high-speed rail passenger lines into major USA city centers.



Mike

[DetroitPlanner]

I'd agree too. Note that while our train is about as automated as you can get, it has 13 stations over a short distance (approx 3 mile loop). It is often quicker to walk to your destination than to take the train. Mind you that this train is entirely grade separated so it has no competing traffic worries.