The trainer's 24" of space is the distance between the cars-the slack can be taken up without warning so,2' is the normal distance used for training since 2' is easier to remember.
You can completely stand between cars (not recommended) without touching either car.
Again as a crewman a fast check in my ETT would tell me Patton's Warehouse had a 450' siding and I knew 8 40' boxcars would fit with the simple math I was taught in class.8 X 42 = 336'. I have plenty of room and was "safe" up to 9 40' cars (378') and still have room to spare to the derail..
There is no complicated math for the crew to do since the ETT tells all.
Larry
Conductor.
Summerset Ry.
"Stay Alert, Don't get hurt Safety First!"
Howdy, Larry.
Just Googled up the 'Standard AAR 40 foot boxcar.' Drawing is dimensioned 42' 0" between striker plates and 44' 5 7/8" between pulling faces. I assume this is with the draft gear completely unloaded.
I recall watching an Erie freight backing up to gather slack - a couple of carlengths of slack. I expect your trainer was referring to hard-buffed cars when he stated two feet. At that, he may have been generous. Isn't there some air space between pulling faces when cars are pushed together?
Chuck (Modeling Central Japan in September, 1964)
I reread your question in railroad speak 2 40' boxcars is 82'-including the 24" red zone between the cars. Railroads back then tried to keep things simple. Less math means less chance of errors.
All we needed to know was our train was 2700 feet and the passing siding was 5,000'. Same for a industrial siding.. Say a industrial siding was 800 feet we knew spoting six 40' or six 50' cars wasn't a issue.
This information was found in our ETT..
Simple yes?
When I took my PRR student brakeman safety classes in '66 the instructor told us new hires there was 24" between cars---24" between you and injury or death.He went on to say never place yourself where you can't move clear if the cut begin to move.
sanduskyIt seem like you would have to add two "knuckle thicknesses" to the total dimension due to the way the couplers fit together when coupled, unless I'm envisioning it incorrectly.
I agree, it's hard to envision. BUT. The coupler "pulling face" is the correct "half-way" distance. It's the ONLY point for two coupled cars where the same point on each car is co-incident.
If you, instead, decide to choose the outer coupler face as a reference point, you end up having to subtract the interlocked distance. Which gets you right back to the paragraph above. The only time you would add the knuckle thickness would be when you were concerned about the overall length of a single car. Say, perhaps a car has to fit in a building between an internal bumper and a roll down door.
Ed
From several drawings of freight cars:
there is a dimension of 12" measured from what we would call the face of the coupler box to the inside face of the knuckle. Here's the comment from the AAR plans:
"INSIDE FACE OF KNUCKLE WITH COUPLER HORN AGAINST STRIKING CASTING"
So, if you've got two (box)cars shoved together so that the couplers are shoved back into the "coupler box" until the head hits it, there should be 24" between the two "coupler boxes". That's with various springs compressed. The dimension would increase when the cars are being pulled. How much?????
I looked through a Car Builders' Cyclopedia from 1953 and came up with 3". Per car. So that 24" grows to 30" under tension.
And that's between coupler box faces.
I'm wondering how far from car end to car end for, say, a pair of coupled 40' "steam era" (apologies to Irv Athearn) boxcars.
Thx