Point machine
Encyclopedia
A point machine is a device for operating railway turnouts
especially at a distance.
s. There are a number of different kinds of levers including throwover levers which stay in the last position thrown, and ball levers which revert to a standard position.
Gradually the turnouts on main lines came to be operated at distances up to about 300m by centralised levers in signal box
es, either by rodding or piping, or by double wire arrangements.
Since the limitation of mechanical operation restricted the design of track layouts on the one hand, and tended to require more signal boxes, even lightly used ones, on the other hand, there has always been a desire of railway administrations to increase the distance that remote turnouts can be operated. This requires some kind of power operation of points and signals. The principal means of power operation include hydraulic, pneumatic and electric.
More recently with the increase in weight of rail, and the introduction of high speed turnouts with finer angles requiring multiple drives, points have become stiffer and beyond the capability of mechanical drives, forcing the introduction of point machines if not already done so.
(aka sleeper) where it is relatively hidden from damage from track maintenance machines.
Railroad switch
A railroad switch, turnout or [set of] points is a mechanical installation enabling railway trains to be guided from one track to another at a railway junction....
especially at a distance.
Overview
In the earliest times, railway turnouts were operated manually by simple leverLever
In physics, a lever is a rigid object that is used with an appropriate fulcrum or pivot point to either multiply the mechanical force that can be applied to another object or resistance force , or multiply the distance and speed at which the opposite end of the rigid object travels.This leverage...
s. There are a number of different kinds of levers including throwover levers which stay in the last position thrown, and ball levers which revert to a standard position.
Gradually the turnouts on main lines came to be operated at distances up to about 300m by centralised levers in signal box
Signal box
On a rail transport system, signalling control is the process by which control is exercised over train movements by way of railway signals and block systems to ensure that trains operate safely, over the correct route and to the proper timetable...
es, either by rodding or piping, or by double wire arrangements.
Since the limitation of mechanical operation restricted the design of track layouts on the one hand, and tended to require more signal boxes, even lightly used ones, on the other hand, there has always been a desire of railway administrations to increase the distance that remote turnouts can be operated. This requires some kind of power operation of points and signals. The principal means of power operation include hydraulic, pneumatic and electric.
More recently with the increase in weight of rail, and the introduction of high speed turnouts with finer angles requiring multiple drives, points have become stiffer and beyond the capability of mechanical drives, forcing the introduction of point machines if not already done so.
Principle
Modern point machines have an electric motor and gears to convert rotating motion of motor into linear motion. The gear assembly also provides required transmission ratio so that it can generate necessary force to move switch blades. The machine performs following functions:- Moving switch blades.
- Locking the blades
- Detection and proving the position of blades.
Point Machine Conversion - Manual to Motorized
A point machine conversion system consist in a remotely controlled device attached to an existing manually-operated point that allows the shunter/driver to remotely operate hand points with a radio handset. Each converter can be used as a stand alone or multiple units can be installed operating together with routing.In Tie Unit
The latest development is to mount the switch motor inside a faux railroad tieRailroad tie
A railroad tie/railway tie , or railway sleeper is a rectangular item used to support the rails in railroad tracks...
(aka sleeper) where it is relatively hidden from damage from track maintenance machines.