[Marxism] Train Collision in DC

[S. Artesian]

Depends.  Everybody, well not everybody, but different railroads have 
different signal design distances, different braking distances based on 
train weight, curvature, grade, braking rates [rate of deceleration], etc.

Metro North utilizes the standard table of braking rates developed by the 
New York Central System in 1933 (?).

Our basis for signal design distance was a ROD, rate of deceleration of .84 
miles per hour/sec.  This is a very conservative, safe, allowance, and many 
railroads are much more aggressive.  We calculated stopping distance for 
freight trains at 3X the distance calculated for passenger trains.

Braking rates achievable under emergency circumstances, venting all brake 
pipe pressure to atmosphere, causing an emergency and irreversible 
application of the brakes, could, under dry conditions, generate rates of 
deceleration up to 2.9 miles per hour/sec, but of course the whole point of 
signal design is to eliminate the need for emergency braking, as even that 
higher rate of deceleration is not enough to stop a train going 60 mph in 
less than 1000 feet.
----- Original Message ----- 
From: "Les Schaffer" <schaffer at optonline.net>
To: <sartesian at earthlink.net>
Sent: Thursday, June 25, 2009 5:48 PM
Subject: Re: [Marxism] Train Collision in DC


> S. Artesian wrote:
>> I know it used to wake me up
>> at night, making me calculate and recalculate signal design distances, 
>> train
>> braking rates, and reviewing the results of safety verification testing 
>> of
>> our signal system.
>
>
> what is the minimum stopping distance for these kinds of trains at these
> speeds?
>
> Les
=