I am curious about how a train prepares to enter a main line when entering from a yard/siding. I suspect that either of the following situation may occur but I am curious which approach is most typical.
1) Train sits in original position in yard/siding then starts moving and entering the main when clearance is given. In effect, train does not move toward the main until it is cleared to enter the main.
or
2) Train moves from yard/siding along through any switches and approaches the main then sits there until it is cleared to enter main. The problem I see with this approach is that the train is probably blocking multiple tracks/switches as it sits there. Would only be used if (a) the approach track is long enough to hold the entire train thus minimizing any blocking action for other trains, (b) the wait time is expected to be very short or (c) the train is considered high enough priority to permit any inconvenience to other trains..
Paul D
N scale Washita and Santa Fe RailroadSouthern Oklahoma circa late 70's
The situation I have seen, at yards and also where branch lines meet main lines, is that the train pulls up to a protective signal and awaits signal indication or dispatcher verbal OK via radio (or a combo of the two).
In the days of train orders the train would await orders and clearance, either physical paper or via radio.
In the yard, the train may be blocking some access to the yard, depending on length, but not yard activity itself. The prototype usually gave itself enough options to avoid having any one departing train shut everything down. We are not always so fortunate in our track planning of course.
Dave Nelson
I would say that either 1 or 2 would be used, at the pleasure of the person in charge of the yard. Under varying circumstances, one or the other would prove the better choice.
Ed