20-02-2009, 02:46 PM
Okay, so effectively it is a legacy figure. That makes sense.
Some work I am involved in is trying to derive brake rates for freight trains of variable lengths/loads. The figures required, although they are the second line of defense, still are required to be realistic enough to stop a train, with a "normal" level of adhesion, in a predicatable yet operable distance. Hence, my hidden question was where is the engineering justification behind the value or was it a reasonable assumption from days of old. The answer appears to be the latter.
When we have some typical freight figures, I'll publish them here. They will make interesting reading based on theory backed up with practical testing.
Some work I am involved in is trying to derive brake rates for freight trains of variable lengths/loads. The figures required, although they are the second line of defense, still are required to be realistic enough to stop a train, with a "normal" level of adhesion, in a predicatable yet operable distance. Hence, my hidden question was where is the engineering justification behind the value or was it a reasonable assumption from days of old. The answer appears to be the latter.
When we have some typical freight figures, I'll publish them here. They will make interesting reading based on theory backed up with practical testing.
Le coureur