Dangers of High Speed Trains Pushed from the Rear
 

"David Hansen" wrote in message
...
On Fri, 12 Nov 2004 01:12:56 +0000 someone who may be Clive Coleman
wrote this:-

Such an interlock appears to have been common since the 1960s.
Not on the 6300s, 800s,1000s,7000s,9500s,1600s or any steam engine I
ever worked on.

Were any of them designed in the late 1950s or 1960s?


--
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I will always explain revoked keys, unless the UK government
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I don't know if it's significant, but I don't believe any of the classes
that Clive notes were designed for multiple (rather than tandem) operation.
Brian

Dangers of High Speed Trains Pushed from the Rear
 

In message , BH Williams
writes
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I don't know if it's significant, but I don't believe any of the
classes that Clive notes were designed for multiple (rather than
tandem) operation. Brian
I don't think the 1000s or 95s were but certainly the 800s and 63s were
equipped and could work under one driver. The 7000s had different
control equipment, orange triangle if I remember correctly, and again
could be worked from a single cab.
--
Clive Coleman

Dangers of High Speed Trains Pushed from the Rear
 

"Roger T." wrote:

It's typical in North America to "power brake".

Wash your mouth out with soap. That practice is discouraged by the
railway companies, as it wastes fuel. Some railways will even
discipline employees if they power brake.

Dangers of High Speed Trains Pushed from the Rear
 

"Roger T." wrote:

Nope, "power braking: is common, even on passenger trains.

The locomotives used on VIA Rail Canada's transcontinental passenger
train are set up like the HST. i.e., if the air brakes are applied, the
power is automatically shut off. That means the drivers cannot power
brake. Other passenger locomotives will allow power braking, but it is
discouraged.

Dangers of High Speed Trains Pushed from the Rear
 

Pyromancer wrote:

Btw, what is the independent brake? We tend to have straight-air on
locos, and automatic air or automatic vacuum on the train.

North American locomotives have a dual braking system. The straight air
system is called the independent brake, since it can be applied
independently of the brake on the rest of the train. Locomotive brakes
will also apply with an automatic brake application.

In typical freight train operation, the driver will "bail off". or
release, the automatic brake application to reduce wheel heating. If
the driver is otherwise incapacitated, the brakes will apply. On
shorter trains, like passenger trains, the driver will typically bail
off the automatic application, then apply a partial application of the
independent, straight air brake to assist in reducing train speeds.

Dangers of High Speed Trains Pushed from the Rear
 

James Robinson wrote:
"Roger T." wrote:

Nope, "power braking: is common, even on passenger trains.


The locomotives used on VIA Rail Canada's transcontinental passenger
train are set up like the HST. i.e., if the air brakes are applied, the
power is automatically shut off. That means the drivers cannot power
brake. Other passenger locomotives will allow power braking, but it is
discouraged.

With the possible exception of the auto train, I believe VIA's
transcontinental train is the longest passenger train in North America.
If power braking isn't needed on that train, then itn't likely to
be needed on very many passenger trains.

Greg Gritton

Dangers of High Speed Trains Pushed from the Rear
 

"James Robinson" wrote in message
...
"Roger T." wrote:

Nope, "power braking: is common, even on passenger trains.

The locomotives used on VIA Rail Canada's transcontinental passenger
train are set up like the HST. i.e., if the air brakes are applied, the
power is automatically shut off. That means the drivers cannot power
brake. Other passenger locomotives will allow power braking, but it is
discouraged.

Didn't know about the newer VIA locos.


--
Cheers
Roger T.

Home of the Great Eastern Railway
http://www.highspeedplus.com/~rogertra/

Dangers of High Speed Trains Pushed from the Rear
 

On Wed, 10 Nov 2004 18:10:58 UTC, David Hansen
wrote:

: The forces the power cars produce are minor compared
: to the forces involved in a crash.

3000hp at 100mph is pretty close to 5 tons of thrust. As David says,
compared to the crash forces on half a train (4 * 35 ton coaches + 1 *
70 ton locomotive = 210 tons), that's trivial.

Ian

--

Dangers of High Speed Trains Pushed from the Rear
 

On Wed, 10 Nov 2004 22:20:42 UTC, Pyromancer
wrote:

: Stopping 350 tons in such a short space requires the
: dissipation of a great deal of energy

350 tons at 100mph (45 m/s) is 1/2 * 350 * (45)^2 = 350MJ which is the
same amount you get if you dropped the entire train from a height of
100m (three hundred feet). Or, if you prefer, 84 kilograms of TNT.

Ian
--

Dangers of High Speed Trains Pushed from the Rear
 

"Ian Johnston" wrote in message
...
3000hp at 100mph is pretty close to 5 tons of thrust. As David says,
compared to the crash forces on half a train (4 * 35 ton coaches + 1 *
70 ton locomotive = 210 tons), that's trivial.

Actually it's even more trivial than that, because the power car's engine
only produces 2250hp, of which (according to a general rule of thumb for
diesel locos) only about 80% would be available for traction even if not
providing ETS. So we are probably looking at 1600-1800hp available for
traction, depending on the ETS load, reducing the calculated thrust to
around 3 tons.

That's still higher than my guess yesterday (2 tons), but that was just a
guess which I thought afterwards might have been a bit on the low side.

Roger