[44 North]

Most modern metros with no legacy concerns use pantos as they're much safer than 3rd rail. Fewer fires, easier rail maintenance/inspections, less concern during emergencies, etc.

Below are most of the cities with wholly new metro systems launched in 2019/2020/2021.

Overhead fixed-rail (or catenary): Luoyang, Taiyuan, Guadalajara, Sydney, Xuzhou, Wenzhou, Jinan, Nagpur, Noida, Changzhou, Hohhot, Jakarta

3rd Rail: Lahore, Ahmedabad, Doha

They do but the cost difference between a 6m tunnel and 7m tunnel is tiny relative to the cost of the project as a whole. I expect they more than make that back from easier maintenance.

Interesting. Honolulu won't have pantos, they'd be like the closest new metro system I can think of (by close I mean US). Hanoi opened and they don't have pantos either. But both are hot locales so maybe that's a reason. I'm sure there are more, but yea it does seem subway pantos are becoming more common.

But let's not discount the costs of tunneling. For a 5km tunnel the difference between 6.5m and 7m is another 25,000 cubic metres of earth, or 2500 dump trucks. Then more concrete for the liners since an added 1.5m circumference (roughly an extra liner). It adds up.

 

[TRONto]

Interesting. Honolulu won't have pantos, they'd be like the closest new metro system I can think of (by close I mean US). Hanoi opened and they don't have pantos either. But both are hot locales so maybe that's a reason. I'm sure there are more, but yea it does seem subway pantos are becoming more common.

But let's not discount the costs of tunneling. For a 5km tunnel the difference between 6.5m and 7m is another 25,000 cubic metres of earth, or 2500 dump trucks. Then more concrete for the liners since an added 1.5m circumference (roughly an extra liner). It adds up.

It wouldn't be the heat. Delhi has a bunch of pantos