Light Rail Vehicles - LRT, ICTS, Monorail, and more

[jamincan]

Are those low traffic situations?

[tomh009]

....hugely outweighs the infinitesimal risk of collision.

Houston says hi

One of the challenges with Houston is that they don't separate cars and the LRT with a curb.  See here:

[ijmorlan]

....hugely outweighs the infinitesimal risk of collision.

Houston says hi

You cut some pretty important qualifiers from what I wrote.

I gave an example of a low-speed, low-traffic situation — a carhouse access — where I suggested it might be handy to have a level crossing, and suggested the risk of collision in those circumstances was tiny. I did not suggest the risk of collision with on-street trackage was infinitesimal. I was specifically trying to avoid a discussion of just exactly why certain systems seem to have a regular problem with collisions and others don’t, even among systems that have significant lack of grade separation.

But in any case this is all irrelevant to my question, which you give the appearance of avoiding and which I now re-word: say you have a city which is considering CityVal. In what way are the concrete tracks and rubber-tired vehicles better than steel rails and standard LRVs? I would argue that they have to be quite a bit better in order to justify their use, because of the reduced flexibility in future extensions of the system, specifically in imposing an absolute requirement for total grade separation on all parts of the system.

[jamincan]

Are level crossing actually impossible with CityVal? Presumably the vehicles have to drive over the guidance rail themselves when switching, so I don't see why cars couldn't as well.

[Canard]

The top of the rail head is flush with the rolling surface for the tires - same as Translohr. There's no reason why they aren't possible in the yard, with a small break in the bus bar.

[ijmorlan]

Are level crossing actually impossible with CityVal? Presumably the vehicles have to drive over the guidance rail themselves when switching, so I don't see why cars couldn't as well.

Good question. I just sort of assumed by the appearance that a level crossing was not possible. I know the supposed impossibility of switching is one of the things monorail enthusiasts find themselves correcting. I’m certainly happy to be corrected about anything I have wrong.

[tomh009]

Are level crossing actually impossible with CityVal? Presumably the vehicles have to drive over the guidance rail themselves when switching, so I don't see why cars couldn't as well.

Good question. I just sort of assumed by the appearance that a level crossing was not possible. I know the supposed impossibility of switching is one of the things monorail enthusiasts find themselves correcting. I’m certainly happy to be corrected about anything I have wrong.

Note that the CityVal trains are fully automated.  Does that impose some additional requirements for level crossings?

[Canard]

There would never be a level crossing. Peoplemovers/AGT and level crossings don't happen - that's the point. They're grade-separated, which is safer/faster/better for all.

I think what might be throwing you all is the photo I posted of the test track, which is at-grade since it's in an enclosed environment at Lohr. Rennes ligne b will be entirely elevated and underground, never at-grade.

[ijmorlan]

There would never be a level crossing. Peoplemovers/AGT and level crossings don't happen - that's the point. They're grade-separated, which is safer/faster/better for all.

I think what might be throwing you all is the photo I posted of the test track, which is at-grade since it's in an enclosed environment at Lohr. Rennes ligne b will be entirely elevated and underground, never at-grade.

And that can be accomplished with LRT also. Again, what can CityVal do that LRT cannot?

I’m genuinely curious, in case you’re wondering. I confess to a strong LRT orientation, but I’m open to a better understanding of why other systems are popular as well.

This is a bit like MacGyver. Ridiculous analogy coming up, which depends on me remembering my MacGyver correctly: the fact that he does not use guns is a strength. The fact that he apparently can not use guns is a weakness.

[Canard]

Well, what you're essentially saying is that this thread is pointless, and the entire world should stop building anything except LRT, and anyone who builds anything other than LRT has made the wrong choice.

I'm really not interested in proving to anyone why I like one system over another, or why I think one is better. You've already formed your own conclusion, and I'm not going to try to sway you.

[ijmorlan]

Well, what you're essentially saying is that this thread is pointless, and the entire world should stop building anything except LRT, and anyone who builds anything other than LRT has made the wrong choice.

I'm really not interested in proving to anyone why I like one system over another, or why I think one is better.  You've already formed your own conclusion, and I'm not going to try to sway you.

I am not saying anything of the kind, and I can’t understand why you would think that I think that. I just don’t understand what is better about rubber tires on concrete tracks with a centre guidance rail as compared to the traditional steel tires on steel tracks, and I’m hoping that people on this thread know more about this and can explain it to me. On the other hand, an unwillingness to even attempt to answer the question does make me suspect that the answer might possibly be that there is no actual advantage. But that is speculative. So, contrary to what you say, my current opinion is that CityVal is an interesting variation on the train concept, and I remain unclear on how it might improve over what can be done in the same right-of-way with LRT.

What I do know is that “it’s grade-separated” is definitely not an advantage of CityVal over LRT, since LRT can be grade-separated. It is however valid to give that as an advantage of any CityVal system over any non-grade-separated system, including ours.

[jamincan]

From wikipedia:

Advantages:
- smoother ride
- faster acceleration
- ability to climb steeper grades
- better braking (allowing shorter headways)
- quieter
- reduced rail wear

Disadvantages:
- less energy efficient (hotter, heavier, more rolling resistance)
- higher maintenance cost on vehicle (tires need replacing)
- reduced air quality due to wear of tires
- weather affects tractions
- possibly more expensive to build

[tomh009]

Clearly for Tokyo or New York, LRT would not be the right choice. But do you really think a monorail or a subway would have been the right choice for us -- even given their advantages?

[Canard]

Sorry, too many years on the defensive with all the monorail haters out there (it's exhausting). Every transit technology has advantages and disadvantages. Jamincan's outlined them perfectly. I've been following the Rennes ligne b project for years because it's exciting to me; I think the vehicles are very attractive, and I like rubber tires.

[plam]

I rode Montreal's metro with rubber tires for quite some years. It was touted as a smoother ride but I still found it quite bumpy.