Eastern Railroad Discussion > Grades on Metropolitan sub-former B&O

Grades from Silver Spring to former QN Tower were in question.
B&O Operating Timetable #91 dated April 28, 1963 shows following altitude profiles:
Gaithersburg 512 - Randolph 358 - Silver Spring just over 300 - Terra Cota - 186 - Washimgton - 0.
When I qualified at QN Tower I was told "If a yard engine working west of the tower sets a car out on No. 1 track,
open the switch to the west wye. Otherwise, If a car gets away and starts to roll, it will go all the way to Union Station.



Edited 1 time(s). Last edit at 05/04/16 10:49 by skrambo.

What you were told was probably true. But only a track chart can tell you what the grade is, and if I have one I cannot look now. A one percent grade is 52.8 feet per mile. That would certainly make any loose car, loaded or empty, roll away. Even grades 1/3 of that will let a car roll; that is why railroads love to build a yard with a 'bowl' in the middle. Cars will roll to the center of the yard and not roll out. Our local yard on CSX is like that and they can 'kick' cars without them getting in the way. With modern roller bearings cars, loaded or empty (some empty cars are very heavy, 50 tons or more) will roll on the slightest of any grade. This is why you see the railroad safety rule to apply a few handbrakes EVEN  when it is know they will roll into a safe grade and apply a one minute hand brake test to make sure cars left standing will not roll away.

The grade in the three miles approaching QN from the west is approximately 0.7%