On
April 3, 2007, headlines all over the world heralded the
World's Fastest Train, the
V150,
a special consist
built by a partnership between Alstom
Réseau Ferré de France and Société Nationale
des Chemins de fer Français. The V150 set a new
world record of 574.8 kph (357.0 mph) on an isolated
section of trackway between Strasbourg and Paris, as
recorded in this video.
The
photograph below shows the V150 exhibited aboard a barge
on La Seine...
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...with some nearby tower in the
background. "V150" was the code name signifying its
targeted speed of 150 m/s. That achievement was marked
about two minutes into the video,
and the train continued to accelerate, reaching a peak
of 159.7 m/s (~175 yards per second). Think of a
couple of football fields passing your train window at
your resting heart-rate..
The
previous
record was 515.3 kph (320.1 mph), set in 1990 by an
Alstom Train à Grande Vitesse (TGV).
The V150 presages the successor to the TGV, which will
be called Automotrice à Grande Vitesse (AGV).
Whereas
the TGV configuration is equipped with powered cars at
the opposite ends of each consist and unpowered
passenger cars in between, the AGV uses self-propelled
vehicles, all producing tractive
effort from the overhead
lines delivered to axles throughout the train.
Passenger seating aboard the AGV will be on two levels
(duplex),
thereby
doubling the AGV's capacity without lengthening the
TGV's stations and platforms.
The World's
Fastest Train draws 19.6 megawatts of
electrical power and develops a total of 26,300
horsepower. Special attributes of the V150
include [1] synchronous, permanent-magnet traction motors;
[2] actively controlled pantograph;
[3] enlarged wheel diameter by 19% to limit the
rotational speed of the powertrain (5,688 vs 8,533
rpm); and [4] aerodynamic improvements -- [a] air dam,
[b] flush-mounted windshield, [c] rigid membranes
filling the space between cars, [d] roof fairings over
the forward pantograph opening -- all resulting in a
15% savings in drag.
Whereas pictures of high-speed trains
invariably feature their streamlined designs from the
front, it is the rear of a body moving through
a fluid that determines aerodynamic
drag more than the front, with the familiar tear-drop
shape being most ideal. Passenger trains must
travel in either direction, so their shapes are
necessarily symmetrical. Those red lights in the
picture on the right indicate that our view is from
the rear of the V150, with 'clam-shells' closed over
its unused coupler. We also see the pantograph
on the rear car, which captures the electric power for
distribution to traction motors throughout the train.
The V150's record-setting runs were
conducted on a customized test-track [a] 88 miles long
at a location chosen for favorable vertical profile,
[b] long-radius curves with [c] superelevation
set higher than standard, [d] catenary
voltages increased 24% to 31 kVac (over standard 25
kVac), and [e] messenger
wire tension pulled tighter than normal by 60%
for mechanical stability.
Solvers
of
two other puzzles, Station Stop
and Trip Time, have taken
into consideration many parameters that limit the
speed of a train between stations in a commuter rail
environment. For high-speed rail travel applying
the World's Fastest Train,
let us simplify and idealize the seven most pertinent
parameters...
- Maximum Train Velocity
~~~~~~~~~~~~~~~~~~~~~~~~~~~~ vMAX = 357 mph
- Maximum Propulsive Power
~~~~~~~~~~~~~~~~~~~ pMAX = 26,300 horsepower
- Maximum Tractive Effort
~~~~~~~~~~~~~~~~~~~~~~ eMAX =
27,600 pounds-force
- Maximum Train Weight
~~~~~~~~~~~~~~~ wMAX=
100 tons = 200,000 pounds-force
- Maximum Acceleration ~~~~ aMAX =
0.1 g = 2.2 mph/sec (limited by passenger comfort)
- Maximum Braking Deceleration
~~~ - aMAX =
- 0.1 g = - 2.2 mph/sec (service brake-rate)
- Station Dwell Time
~~~~~~~~~~~~~~~~~~~ tDWELL
= 5 minutes (enroute railway station)
A typical distance between stations in
high-speed train service can be as short as a few miles
or more than 100 miles. For example, the planned California
High
Speed Rail project has eight intermediate stations
between Sacramento and Los Angeles along a route 412
miles in length. The segments range from 13 miles
to 113 miles, with the average being 412 / 9 = 46
miles. At its record-setting speed of 357 mph, a
V150-class train could theoretically complete the trip non-stop
in about 1:09.
What would be your estimated overall
speed for the same trip, making stops as
indicated in the table below?
Intermediate
Stations
|
{a}
mph
|
{b}
mph
|
{c}
mph
|
{d}
mph |
0
|
357
|
357
|
357
|
357
|
1
|
333
|
310
|
321
|
|
2
|
312
|
275
|
292
|
|
3
|
293
|
246
|
268
|
|
4
|
277
|
223
|
247
|
|
5
|
262
|
204
|
229
|
|
6
|
249
|
188
|
214
|
|
7
|
237
|
174
|
201
|
|
8
|
227
|
162
|
189
|
|
GO TO
SOLUTION PAGE
|