Comment by bluGill

1 day ago

A tram and train are the same thing. No difference at all.

There are different modes of operation that differentiate them but fundamentaly they are all trains and face the same issues

They operate in completely different scenarios. They’re the same shape, but they’re a different set of hardware, constraints, accessibility, need to be scheduled in a different way to account for traffic, different safety concerns, different signalling systems, different distances, different surroundings.

Again I sorta see what you mean, but feel you’re massively over simplifying this.

  • I mean trams basically are street-running trains. The light rail/heavy rail distinction is more one of weight and size than actual issues.

    Ceci n'est pas une tram: https://www.youtube.com/shorts/kMUANU9H6aw

    https://en.wikipedia.org/wiki/Rubber-tyred_metro and https://en.wikipedia.org/wiki/Guided_bus also exist.

    (For me, the big thing about trams and trains and subways, etc is that the track is a kind of social construct - the track tells me that eventually a vehicle will come for me - no need to really worry about timetables, etc. A bus, a bus may come, maybe it won't. It's all psychoillogical but it's there the same.)

    • Maybe another analogy:

      A tram is a golf cart or ATV A train is a highway bus

      They have different applications and contexts in which they operate, even if they have core similarities

    • The fundamental operational principle is different. Trams operate (typically, on street running sections) on sight - they are responsible for monitoring traffic, and stoping if necessary. Contrast with the block-based approach used for trains, especially in combination with Euro-style positive train control systems.

Your comment contradicts itself.

The second sentence is partially true: they do have different modes of operation.

But no, they don’t face entirely the same issues. Trains should hopefully never routinely encounter cars sharing their track and they don’t have to make tight turns to follow existing roadways.

  • Modern European trams are increasingly grade-separated. See what Marco Chitti has to say about European road design.

Well then there's no difference between overground and underground trains. But it's pretty clear that there are different issues facing building new metro lines.