amtrakowitz wrote:goodnightjohnwayne wrote:jamesinclair wrote:Also, California is aiming to have a test track segment online by around the same time. It's been stated that current San Joaquin Amtrak trains may run at 125mph on the segment until the full line and new trainsets are ready
Now, what is going to pull those bilevel coaches at 125MPH? No existing diesel locomotive is geared for that speed, and if you did regear one for 125MPH speeds, acceleration would suffer
How greatly would acceleration suffer, in reality? especially since locomotives like the P42DC are currently certified for 110 mph but might be able to hit 125 mph with as-built gearing.
I've seen absolutely no proof that an existing, unmodified Genesis can be used in routine, revenue service at a sustained 125MPH. It's also worth noting that the State of California bought the F59PHI, not the Genesis. I'm not saying the Blomberg trucks aren't good for relatively high speeds, but these locomotives just aren't geared for that speed.
goodnightjohnwayne wrote:nasadowsk wrote:Right now, AFAIK, the FRA hasn't set track standards / rules for faster than 150. Not like the FRA's standards at 150 are anything impressive. Tier II and keep the track somewhere close to in gauge. IIRC, Germany is +- a few mm at that speed. The FRA's more like an inch or two
That's an ill-informed exaggeration. In reality, the FRA does have well thought out standards, although there is currently no dedicated passenger train trackage in North America requiring standards for operations above 150MPH
Looks more arbitrary than "well thought out" to me. They do have written standards for so-called "Class 9" track, which is supposed to permit operation at 200 mph; the
gauge limits for Class 9 are between 4' 8¼" and 4' 9¼", which is a half-inch narrow to ¾" broad. I can't find the UIC gauge limits at high speed operation online (all I see is "1435 mm", which is 4' 8½" and no other gauge variability stated); they use lighter rails on high speed tracks in Europe (120 lb/yd on LGVs in France, for example).[/quote][/quote]
In the absence of heavy freight, it's quite possible to use lighter rails, and it's worth noting that tie spacing and general maintenance have more to do with speeds than the weight of the rails.