Chapter: Civil : Railway Airport Harbour Engineering : Railway Engineering : Track Junctions and Simple Track Layouts
Railway Track Junctions: Scissors Crossover
Scissors Crossover
A scissors crossover (Fig. 15.12) is meant for transferring a
vehicle from one track to another track and vice versa. It is provided where
lack of space does not permit the provision of two separate crossovers. It
consists of four pairs of switches, six acute crossings, two obtuse crossings,
check rails, etc.
The scissors crossovers commonly
used are of three types depending on the distance between the two parallel
tracks they join. A brief description of these crossovers follows.
(a) In the
first type, the acute crossing of the diamond falls within the lead of the main
line turnout. In this case, the lead of the main line turnout is considerably
reduced and hence this is not a satisfactory arrangement.
(b) In the
second type, the acute crossing of the diamond falls opposite the crossing of
the main line turnout. Here, both the crossings lie opposite each other,
resulting in a simultaneous drop of the wheel and this results in jolting. This
is also not a desirable type of layout.
(c) In the third
type of scissors crossover, the acute crossing falls outside the lead of the
main crossing. Thus, the acute crossing of the diamond is far away from the
crossing of the main line track. This is the most satisfactory arrangement out
of these three layouts.
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