Highest possible speed for California/Surfliner cars?

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Cal

Cal

Engineer
Joined
Jan 23, 2021
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Location
Socal
I'm curious, would these cars be able to support passenger speeds of 110-125? According to Wikipedia (which is definitely not always right), they can. Curious to think what you guys think.

And do you think it would ever be worth it or possible to upgrade speeds to 100, 110, and maybe more sometime in the (distant) future?
 
jis said:
I think building new cars that are not capable of 125mph given capable enough track and signaling/control infrastructure in this day and age is kind of silly.
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If unclear, I'm talking about the current bi-levels in use on the California services
 
jis said:
125mph today is what 80mph was after WWII.
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This is rather ironic --- in that there were quite a few passenger trains running 90 or 100 right after WWII, until new government regulations required them to slow down in the early 50s.

One has to wonder if there would have been a serious attempt at faster service in the 50s without that.

As for the state of affairs today... if I were buying intercity equipment today I wouldn't feel much pressure to design for faster than 90, though there may be some other reasons (like a common design for NEC and non-NEC coaches) that justifies making everything good for 110.
 
Siegmund said:
This is rather ironic --- in that there were quite a few passenger trains running 90 or 100 right after WWII, until new government regulations required them to slow down in the early 50s.

One has to wonder if there would have been a serious attempt at faster service in the 50s without that.

As for the state of affairs today... if I were buying intercity equipment today I wouldn't feel much pressure to design for faster than 90, though there may be some other reasons (like a common design for NEC and non-NEC coaches) that justifies making everything good for 110.
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I think all coaches should be made-good for 125 at least. Because if by luck theres a chance to upgrade the line to faster speeds, they won't need to complete any tests or purchase new cars to get a higher maximum speed allowed.
 
It sounds to me like the original specs were for 110 MPH for the Surfliners and 125 MPH for the remainder of the California Cars. Is there any reason to question whether or not the commonly cited specs are incorrect?

Certainly the new cars on order are supposed to be built to that standard. If the speeds ever increase, I'd think they'd be mixing new and old equipment and would be relying on the specs to be met.

4.2 General Requirements​
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The carbody shall be designed to the normal and expected base set of requirements established by 49CFR Part 238, APTA Standard SS-C&S-034-99 and this specification. The Crash Energy Management (CEM) recommended practice in Section 6 of APTA Standard SS-C&S-034-99, rev 2 shall be met with the crush-based approach specified in this Specification. Crash Energy Management (CEM) features are required as an overlay on the base set of requirements. CEM requirements are based on the results of FRA research to date as described in the various FRA technical papers and presentations that can be found on the Volpe Center website listed in Chapter 2.​
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The completed carbody structure shall be designed and constructed in full accordance with all applicable Federal and State rules, regulations and requirements for cars operating in trains, at speeds of up to 125 miles per hour (mph) (201 km/hr).​
 
I would also hazard a guess that top design speed also has to do with parts. If all the parts being made are going to be capable of 125, why design special parts that can go slower? It could be a literal case of don't reinvent the wheel.
 
Structures are only part of the game. Remember each car type has to be qualified for a top speed. The regs require each type to be qualified at 10% over max qualification speed so for 125 MPH car has to be tested to at least 137.5 MPH. The 110 Qualified cars would only have to be tested to 121 + MPH. The testing has been done at the test track in Pueblo. The V-1s were only qualified to 110 whereas the V-2 are qualified to 125. It is rumored that Amtrak has modified some V-1s to 125 but not all are modified yet so Amtrak still has a blanket 110 for LD trains with V-1s in consist.

An exception are the new Acela-2s. Pueblo did the incremental testing to their max speed and then additional higher speeds rest are up to Amtrak on the NEC . So for the desired 160 for AX-2s the test train needs to test exceed 176. It is rumored that on the NJ speedway the AX-2 had PAN contact problems at some speed less than 176 but several solutions are being tried.
 
It's the alignment that becomes the issue. Unless distances are very long between lower speed segments very little is to be gained in going 125 mph instead of 110 mph or even 90 mph. One writer quite a few years ago said, the best way to go fast is to avoid going slow. If the 25 mph or less over the last mile or few miles in major stations could be raised to 50+ far more in time reduction could be gained. Case in point, LAUS probably has a mile or a few miles of 10 to 15 mph into the place.

I am not saying this to say there is no need to go for 125 mph equipment. I think you should, if not for more, just saying the time reduction benefits of a 125 mph maximum are likely to less or even far less than expected.
 

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