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Comment by melling | Hacker News Reader

The last mile has been solved?

Now we simply need to make the 50-75 miles in-between more bearable. Hopefully, someday soon we’ll be covering that vast distance at the incredible speed of 100 mph (160 kph)

https://www.cnn.com/travel/article/china-driverless-maglev-t...

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> Hopefully, someday soon we’ll be covering that vast distance at the incredible speed of 100 mph (160 kph)

> https://www.cnn.com/travel/article/china-driverless-maglev-t...

Intercity / regional trains are already a thing, and 160kph or so is a standard top speed for them e.g. Class 387, SNCF Class B 81500, …

[0] https://en.wikipedia.org/wiki/Régiolis

[1] https://en.wikipedia.org/wiki/SNCF_Class_B_81500

Currently the main problem is that trains run late, mostly due to insufficient infrastructure and old stuff breaking down. Sometimes accidents or mismanagement.

In the US , the problem is dedicated Rail ROW to run intercity trains at a frequency where they are actually competitive with the car. Otherwise ROW acquisition tends to sink most proposals, and this not counting the actual construction costs

> Now we simply need to make the 50-75 miles in-between more bearable.

Mine is 15 miles, and the problem is stops (which top speed does nothing to address).

You're being a little vague so it's impossible to analyze.

However, if your average speed is 25 mph and the average doubled to 50 mph, I'm sure you'd be happy. With maglevs, we'd probably want more express trains.

My point is that top speed is only relevant when a train can reach it. If a train stops every two miles or less (like mine does in the morning), the vast majority of the time is spent accelerating, decelerating, or stopped.

Is your train an electric multiple unit? Those have far lower stop penalties.

Rolling stock acceleration is specified & designed based on requirements which is based on passenger safety & comfort (especially on regional / intercity trains) rather than rolling stock constraints: https://link.springer.com/article/10.1007/s40864-015-0012-y

Modern "diesel" trains are diesel electric, outside of large freight trains the motors don't really strain to accelerate.

> If the top speed is 160 km/h, then a good EMU has a stop penalty of about 45 seconds, a powerful electric locomotive about 135 seconds, and a diesel locomotive around 190 seconds. With short dwell times coming from level boarding and wide doors, EMUs completely change the equation for local service and infill stops, making more stops justifiable in places where the brutal stop penalty of a locomotive would make them problematic.

-- https://pedestrianobservations.com/2018/06/28/the-value-of-m...

For example, I'm visiting the Bay Area this morning and Caltrain (diesel locomotive) has acceleration much lower than BART (electric multiple unit). Acceleration here is determined by what's practical with the equipment, not the maximum forces people can currently handle.

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