I've traveled on high-speed trains in Europe, including on
engines of both TGV and ICE trains. Some photos here:

http://www.robl.w1.com/Pix-2/high-spd.htm

It's important to understand that in Europe, high-speed
trains operate on three types of lines:

Heritage/legacy: These are the lines in and out of city
centers and major existing stations. On these lines, the
trains operate at lower speeds and are likely to share the
tracks with some freight trains as well as slower standard
passenger trains.

Upgraded: These are existing intercity lines which have
been improved to allow higher operating speeds. These lines,
often four tracks in denser corridors, are likely to also
handle freight traffic on some of the tracks -- and even
some fast freights on the tracks normally used by
passenger trains during the off-peak times for passenger
traffic.

(Most modern long-distance European passenger rolling stock
of the non-high-speed variety is now capable of operating
at speeds up to 160 mph. These trains also fit in well
on the upgraded lines.)

Dedicated: These are the true high-speed lines where trains
operate at 150+ mph. No freight trains (other than work
trains for track maintenance) use these lines.


Typically, a high-speed train will leave a major city station
on a heritage line, then transition to an upgraded line,
before reaching the dedicated high-speed line.

Many of the high-speed trains operate beyond the extent of
the dedicated lines to keep passengers from having to
change to another train, particularly on lines where it
would not be economical of feasible to build new high-speed
lines.


For many years "air mail" between Paris and Lyon, two of the
major cities in France, has moved by TGV trains.


One factor that's often not understood when discussing the
possible mix of passenger and freight is that not all freight
trains are created equal.

U.S. intermodal equipment is quite capable of operating in
the 70 mph range and actually does on lines that are suitable.


Most U.S. proposed high-speed lines would fall in the range
of upgraded/dedicated. Unless you are going to run high-
speed trains around the clock at short intervals -- which
would be highly unlikely, there is no reason not to use
the unused track capacity to run fast intermodal trains on
these lines.

If the proposed Southeast High-Speed Rail Corridor --
Washington, D.C., to Charlotte, N.C., and beyond, ever gets
built -- considerable engineering work has been done -- it
would certainly make sense to run intermodal trains at night.
That would help recover some of the investment in the line.


No, you don't want coal drages and slow local freights on
high-speed lines, but, as a previous poster indicated, if
you can keep traffic at about the same speeds, you can
mix passenger and freight. One reason for the much shorter
freight trains in Europe is that these trains fit much
better in with the mix with passenger traffic on normal
lines. Even on mountain lines with fairly steep grades,
European freight trains typically operate at almost the
same speeds as many intercity passenger trains.

-- Ernest