# HSR detail questions.



## AmtrakPDX (Feb 1, 2010)

Assumptions:

The 'new' HSR trains; will they be electric? Overhead or beside the track (is that called 3rd rail?)

Will the 'standard' Amtrak trains be able to run on the same track?

Will the 'new' HSR trains be as tall as the Superliners?

I'm sure that they have to manage a switch sometime during their travels but what is the max speed they can negotiate switches?

For the proposed HSR lines they have now there doesn't seem to be a practical need for 'sleeping accommodations'. (Dreaming here...) IF there were an LD HSR, would that design include roomettes?

TIA!


----------



## DET63 (Feb 1, 2010)

I would assume that the HSR trains will be electric, with overhead catenary supplying the power. Issues that might have to be determined would be AC vs. DC, voltage, etc.

If new track is built, it would probably be dedicated to high-speed passenger rail. Whether "conventional" passenger trains would be allowed to also use the track might depend on the frequency of the high-speed trains.

The loading gauge of the HSR trains would have to be determined. Perhaps something on the order of the TGV Duplex trains would be developed. I don't know how much vertical clearance would be required, but I would assume there is some sort of minimum distance for the wires above the tops of the cars that has to be maintained for passenger safety as well as to prevent damage to the equipment. I don't know the details, though.

Switch designs would have to allow some track changes at fairly high speeds, but probably at speeds much slower than those of trains not diverging. Switches would of course be necessary (presumably) at stations served by some but not all trains. Trains would have to reduce speed to enter the station and stop, but they'd have be able to going at a fairly fast speed nonetheless in order to not delay trains behind them waiting for them to clear the main so that they can pass while the stopped train is in the station.

I don't know if there are any long-distance highs-speed trains anywhere in the world. My guess is that HSR trains traveling any distance would include some sort of business-class service similar to what is offered on Acela. But could there be an overnight HSR service with sleeping cars? I don't know.


----------



## jis (Feb 1, 2010)

DET63 said:


> I would assume that the HSR trains will be electric, with overhead catenary supplying the power. Issues that might have to be determined would be AC vs. DC, voltage, etc.


I would be very very surprised if it is anything other than high speed constant tension catenary carrying 25kV 60Hz AC, like is used in every other HSR system in the world (well 50Hz countries use 50Hz instead of 60 Hz of course.... whatever the commercial power supply frequency is). Of course since we do have a penchant for wasting scads of money studying everything a dozen times, it is entirely possible that we will spend the next ten years in indecisive bewilderment on this issue. But I hope not.


----------



## Eric S (Feb 1, 2010)

I suppose it depends which high speed trains you are talking about. Trains for the new/proposed California and Florida lines will (almost certainly) be electric, with power supplied by overhead catenary. Same thing with any new trains for the Northeast (to eventually replace the Acelas?). For the Northwest, Midwest, and Southeast upgraded lines, trains will (very likely) be diesel powered.


----------



## George Harris (Feb 1, 2010)

Since I am working on one of these things, I have to be fairly careful in what I say as if it has not already been released to the public, I cannot say it, and I won't, so don't bother asking for any "inside" information.

25kV AC at "coffee pot" frequency, that is 60 cycles/second in the US, is being treated as a given. That is what was used on the New Haven to Boston, and is used by all other major high speed systems in the world. Exception: I think the Italian Directissima may use 3kV DC, because that is what is the standard in Italy, but would have to look it up to be sure. Overhead wire constant tension catenary also. Any serious study on this issues is most unlikely.

Of the equipment sets under consideration, the widest is the Japanese Shinkansen sets, which are 3380 mm wide. That is 11'-1". This is slightly wider than the standard AAR "Plates" which are 10'-8" wide. The European equipment is somewhat narrower. There was a report on these varios types of equipment that appeared in an AREA Bulletin something like 20 years ago. These basics have not changed since.

The standard height limit for the Japanese equipment outline is 4500 mm, and the standard wire height they use is 5100 mm. Gap is 600 mm between maximum vehicle height and wire height. With slight rounding, these are 14'-9", 16'-9", 2'-0". There is a set of European clearance gauges which all equipment used in run-throughs is Western Europe must clear. The highest of these is about the same as the Shinkansen limit. These facts should be a hint that the high speed vehicles will not be as tall as a superliner, although there is no particular reason that make is either impractical or impossible.

Unless a higher overhead wire height is used, the Superliners cannot run on the high speed tracks as the electrical clearance would only be about 6 inches, and even if acceptable in theory (I don't know), would you want to have a big chunk of metal filled with people within 6 inches of a 25 kv bare wire?

There are turnout designs for 100, 130, 160, and 220 km/h (call it 60, 80, 100, 135 mph) found in German standards. Not to say that these would be used exactly, but that such designs exist.

There are FRA rules about what traffic can be run on tracks that are cleared for very high speeds.


----------



## jis (Feb 2, 2010)

George Harris said:


> 25kV AC at "coffee pot" frequency, that is 60 cycles/second in the US, is being treated as a given. That is what was used on the New Haven to Boston, and is used by all other major high speed systems in the world. Exception: I think the Italian Directissima may use 3kV DC, because that is what is the standard in Italy, but would have to look it up to be sure.


The new high speed lines in Italy are all 25kV 50Hz AC. The problem with 3kV DC for HSR is that the catenary becomes too heavy to be able to supply the necessary current and that creates mechanical problems of standing waves etc. in the catenary when a panto passes by at high speed. It is apparently necessary to have as light weight a catenary as possible to avoid these problems.



> Overhead wire constant tension catenary also. Any serious study on this issues is most unlikely.


Yes, I was being a bit tongue in the cheek on that remark. There is really is no necessity to re-invent that particular wheel.


----------

