12 Comments
author

Interesting, again. I started from the cited numbers in the Interim Report.

The cynic in me says that the LR capacity per car has been increased to crush levels.

Post-Covid, people may not ride under those conditions.

Expand full comment
author

I had not noticed that. Interesting, but I would not give it too much significance. However, I have received vague assurances that suggestions would be considered.

Expand full comment

In summary Light Rail is not compliant with FRA regulations because of the specifications to which they are built. Street running is mostly banned in NYC due safety issues in the 1930s-50s.

Expand full comment

Is the 35 mph speed limit only in the Interim Report? The PEL report's LRT and CR track plan and profile both have 45 mph speed limits for the majority of the route, with a 15 mph section near the BAT, a 20 mph southern approach to the East NY Tunnel, and 35 mph street running for LRT. It's funny that they listed 35 mph as the street running speed limit even though they have 100 ft curves (even with the property takings), which would be 0.82 g or 18 mph/s of lateral acceleration, so I don't know where they're coming up with these speed limits from. I'm not sure why they wouldn't just use the same 55 mph speed limit of the subway.

Expand full comment
author

- The PEL Report does not duplicate or revise an number of parts of the Interim Report, including the pages my articles cited on times and speed.

- We should not confuse speed limits with maximum running speed in normal operation.

- Because of closeness of stations, there probably is not much advantage to a higher max. running speed. Indeed, from my observations, around 35 mph top running speed appears to be common on NYC Transit where there are similar station spacings .

- Average street running speeds would be constrained by traffic and left turns. The NYC Truck Smart Guide, p. 11, at https://www.nyc.gov/html/dot/downloads/pdf/ trucksmart-guide.pdf says "A safe left turn is 5 MPH."

Thanks for your great comments.

Expand full comment

I saw that you saw the PEL report modeled the CR option using LIRR cars and operations, which led to the falsely higher running time. They also likely included LIRR's operating costs, such as having a conductor checking tickets. Without the need for that kind of a conductor, much less the possibility of full automation, operating costs should be much lower and not higher than LRT.

Expand full comment

As the Tech Transit Association video says, the existing subway rolling stock can't be used because it's compliant with FTA but not FRA, and the IBX will have to be FRA-compliant.

https://www.youtube.com/watch?v=cmPgqj6wP7o

Expand full comment
author

TTA video was a bit confused on that point. Basically, compliance issues are the same for existing subway stock and light rail. Khyber Sen's comment is correct.

Expand full comment

PATH PA5 cars, and perhaps R211S SIR cars, are somewhat FRA compliant though. They are not fully FRA compliant, but they do receive FRA waivers, and if the IBX uses the same cars, I think it's likely the IBX could get similar FRA waivers.

Also, LRT is definitely not FRA compliant at all either. To mitigate that, they currently plan to build a wall between the IBX and freight tracks, along with an intrusion detection system. If FRA waivers cannot be obtained, they can always build that same wall for subway cars.

Expand full comment

The R211s are not FRA compliant at all since the SIR is no longer under FRA jurisdiction.

M3 like cars would be a better option for flexibility.

Expand full comment

Did you see that the IBX interactive map on their website to also include a line through the cemetery in addition to the street running route? I hope that indicates that they are reconsidering a shallow tunnel underneath the cemetery.

Expand full comment

Where did you get the peak load numbers from? The numbers I saw in the PEL report (page 177) were higher. It said they estimated a peak load of 1287 riders for LRT near Flatbush in the peak 15 minutes. And 1382 for CR. That's already higher than the capacity of 360-person LRVs every 5 minutes (the peak frequency feasible with street running).

Expand full comment