by Newfie » Wed 13 Aug 2014, 22:16:48
$this->bbcode_second_pass_quote('', ' ')Even getting the Acela to travel at 160 m.p.h. for longer stretches will require laying new track, building new tunnels and replacing signals.
Yes to all that. But also to replace bridges.
But even more so would be to take by public domain much now valuable adjacent land so that turns could be straightened out. The turns are killer.
Look, to make true high speed rail you need to build the system from the ground up, quite literally. If you have ever watched them build an interstate you will get a minor idea of what goes into a high speed rail system. The whole sub structure for about three feet down needs to be constructed with varying grades of material so that it supports the rail, absorbs the shock load, drains off water, and does not heave in a hard freeze. Also the spacing between adjacent rail sets is further apart so as to limit the shock and suction between two trains passing.
The current NEC where not built to these standards. Also the rail bed is quite old and was not maintained well for many years. The sub ballast gets so damn hard you quite literally need a jack hammer to get through it. Amtrak has spent tons of money to "undercut" the existing system in order to improve these conditions and get the speed up to where it is. But. They are pretty well pushing the limits of the available technology and what makes sense given the other limitations.
For example consider the catenary system. It is by and large a constant fixation/variable tension system, because that was the state of the art in the 1930's. That means the wire sags when temperatures get high and tightens in cold spells. So above certain temperatures they have to limit the trains speed because the wire is too loose. Of course in a cold snap the wires get tight enough to pull apart. The same things happen to the rail, which is why is has to be temperature compensated (heated with big torches) when the final welds are made.
Constant tension catenary fixes the above issues but when you do loose a piece is not a 500 foot span, but a mile or two comes down. Trade offs.
Now the catenary poles where laid out to accommodate 1930's track spacing' sand speeds. If you want the trains to go significantly faster, then you need to re space the tracks, but then the catenary poles ( and foundations, bridge abutments, culverts, utility crossings, roadway over and underpasses, etc) are in the way. So the whole damn catenary system needs to come down and be redone.
But in the meantime all the commuters rely upon their daily service to get to and from work. So you can either shut down the system, tear it out, and redo it OR you need to do the equivalent of lane closures over a bridge under repair. Just one big ass bridge from DC to NYC. Fun job.
I was PM on a systems contract that was one of seven prime contracts which did a very small scale ( by comparison) version of this on SEPTA in Philadelphia. The job went well. But I got to live for 5 years what this kind of effort takes. And all we were doing was restoring the system to a state of good repair with very minor improvements.
Once you start looking into the details of what is really and truly required converting the NEC to much faster than it is now faces hugh obstacles. Not just in cost, but in finding the public motivation.