Hacker News new | ask | show | jobs
by Incipient 1020 days ago
A car can typically stop within 5-10m at most city speeds (reaction time notwithstanding) and not really waste much energy in the process. A freight train probably takes about a month to stop, at the cost of a lot of energy/fuel. It absolutely makes sense they have right of way.
3 comments

Cars waste exactly as much specific energy coming to a stop from a given speed as a train (or anything else) does. City speeds are limited precisely because otherwise the stopping distance would be too great. If you're driving 25mph in a city and someones jumps out in front of you and you hit them, you're not going to get blamed. If you're driving 65mph you will.

It only "makes sense" for trains to have unimpeded right of way if you're prioritizing corporate expedience over human life. Within my point there are still two main ways trains can move at high speeds - bridge crossings and crossing gates with positive control. If railroads want to operate at high speeds, then they should have to fix their infrastructure rather than being allowed to continue to dumping their externalities onto the public.

Of course "specific energy". You're either unaware a train is significantly more massive than a car, or you're deliberately trying to mislead with your statement. Neither is encouraging.
I would say that focusing on the total big number is deliberately misleading. When the goal is to accelerate (decelerate) mass using the friction created by the weight of the mass itself, the amount of mass cancels out. Likewise when the goal is to transport mass, then cost per unit mass is what matters.

As I said in another comment, we don't condone SUVs or tractor-trailers ignoring red lights just because they're heavier.

> at most city speeds

This is exactly it! Their speeds are limited around areas they're likely to interact with people to enable this. Agreed that slowing them down probably is wrong but they should definitely be protecting crossings.

They could send a drone ahead?