I'm thinking a two part answer, which may not be 100% correct. The same sign can tell them when the engine leaves the yard limits. It may not be critical for the engineer to know when the end of the train has left, as he obviously has/had authority for his move in the yard, and has the authority for the move out of the yard.
Jeff But it's a dry heat!
The question posted reminds me of a local road construction project. A municipalty was replacing a short bridge over a creek and had the road closed for about 5 weeks. Heading south on the road you need to travel over a mile to gain access to a detour around the site and from the detour to the bridge they had bridge out signs every few hundred feet. On they last sign, about 100 feet from the creek, was spray painted on the sign back, "WHICH BRIDGE OUT SIGN DID YOU NOT UNDERSTAND?".
Which brings to mind, would the sign be labeled on both sides?
Vail and Southwestern RR wrote: I'm thinking a two part answer, which may not be 100% correct. The same sign can tell them when the engine leaves the yard limits. It may not be critical for the engineer to know when the end of the train has left, as he obviously has/had authority for his move in the yard, and has the authority for the move out of the yard.
Trains need explicit permission to leave yard limits so a crew without permission needs to know the limit to where it can move the train. Crews also need to know when they are within yard limits so speed can be adjusted to no more than permitting stopping in half the visible distance (excepting first-class trains). The advantage of yard limits is the great freedom trains have to operate within them. A single yard limits area can be quite a distance and include several towns and yards, such as from Elmhurst to San Pablo (collectively called the "Oakland yard"), a distance of 20 miles on the old SP.
Mark
markpierce wrote:Trains need explicit permission to leave yard limits so a crew without permission needs to know the limit to where it can move the train.
Actually exactly the opposite. Yard limits allow any train or engine to occupy the main track, clearing the times of first class trains (with a few other restrictions regarding signals through YL). No require for permission to entire or permission to leave.
Crews also need to know when they are within yard limits so speed can be adjusted to no more than permitting stopping in half the visible distance (excepting first-class trains).
The advantage of yard limits is the great freedom trains have to operate within them. A single yard limits area can be quite a distance and include several towns and yards, such as from Elmhurst to San Pablo (collectively called the "Oakland yard"), a distance of 20 miles on the old SP.
True but the limitation is that trains then have to operate a veeeerrrrrryyyyyyy slow speeds for 20 miles. So if a train has to move at 10 mph to be able to stop, than means it will take it over 2 hours to negotiate the YL.
As to how the engineer knows when he's in Yard Limits, the yard limits are listed in the timetable and he is supposed to know where they are. In addition that is a yard limits sign at the entrance to yard limits (which is also the exit.) So when he goes by one sign he's in yard limits and when he goes by the other one he's leaving. And the last thing is yard limits ONLY applies to the main track. Yard limits do NOT apply to any yard tracks.
Dave H.
Dave H. Painted side goes up. My website : wnbranch.com
Larry
Conductor.
Summerset Ry.
"Stay Alert, Don't get hurt Safety First!"
dehusman wrote: markpierce wrote:Trains need explicit permission to leave yard limits so a crew without permission needs to know the limit to where it can move the train.Actually exactly the opposite. Yard limits allow any train or engine to occupy the main track, clearing the times of first class trains (with a few other restrictions regarding signals through YL). No require for permission to entire or permission to leave.Dave H.
Dave, you misread my comment by 180 degrees. A train can't leave yard limits without specific authority: a statement you agree with.
Mark you're half right.
Trains operating of Timetable or Train Order authority my enter and leave Yard Limits without permission. Only crews operating without TT or TO authority may not leave Yard Limits.
Nick
Take a Ride on the Reading with the: Reading Company Technical & Historical Society http://www.readingrailroad.org/
nbrodar wrote: Mark you're half right.Trains operating of Timetable or Train Order authority my enter and leave Yard Limits without permission. Only crews operating without TT or TO authority may not leave Yard Limits.Nick
By "permission" I meant either through timetable, train order, warrant, CTC signal or whatever the railroad's rules allowed.
markpierce wrote:Dave, you misread my comment by 180 degrees. A train can't leave yard limits without specific authority: a statement you agree with.
Sorta maybe.
A train needs no permission to enter or leave yard limits.
A train does need authority to occupy the main track beyond yard limits in order to leave them.
But that can be the same authority they had before they entered yard limits. If I cut a running order from Anna to Fay and there is yard limits at Dora, they don't need any "specific" authority to leave, they have all the authority they need to leave when they arrive. Maybe its semantics but I don't want to leave the impression that a train needs some specific form of order to leave yard limits.
Perhaps I should limit my discussions on railroad operations to this site:
http://groups.yahoo.com/group/Ry-ops-industrialSIG/