Systems of working Passing loop

1 systems of working

1.1 main , loop
1.2 platform road , through road
1.3 , down working
1.4 dead-end siding

systems of working
main , loop

the main line has straight track, while loop line has low-speed turnouts @ either end. if station has 1 platform, located on main line.

if passenger trains relatively few in number, , likelihood of 2 passenger trains crossing each other low, platform on loop line may omitted.

platform road , through road

the through road has straight track, while platform road has low-speed turnouts @ either end.

a possible advantage of layout trains scheduled pass straight through station can uninterrupted; not have reduce speed pass through curve. layout used @ local stations many passenger trains not stop.

since there 1 passenger platform, not convenient cross 2 passenger trains if both stop.

an example scone railway station, northern end later rearranged resemble main , loop configuration. disadvantage of platform , through arrangement speed limits through turnouts @ each end.

up , down working

in example layout shown, trains take left-hand track in direction of running. low-speed turnouts restrict speed in 1 direction. 2 platform faces needed, , can provided either @ single island platform or 2 side platforms (as shown). overtaking not possible @ kind of up-and-down loop of necessary signals absent.

crossing loops using up-and-down working common in british practice. 1 thing, fewer signals required if tracks in station signalled 1 direction only; also, there less likelihood of collision caused signalling train onto track reserved trains in opposing direction.

the speed restriction in 1 direction can eliminated higher-speed turnouts, may require power operation, longer , heavier high-speed turnouts may beyond capability of manual lever operation.

dead-end siding

it possible cross trains @ stations equipped siding. @ bombo, australia, crossing loop had no platform, , freight trains became longer became inadequate hold them.

molong used have short loop, replaced long stretch of former branch line, dead-end siding.

berry has had short loop removed , shorter dead-end siding substituted. long freight trains not need cross each other here, , freight trains can cross passenger trains waiting in short siding provided freight train arrives second , leaves first.