Trailable facing points at crossing loops
Crossing loops on lesser used railway lines are often provided with trailable facing points, which removes the need for staff on the ground or remote controlled signalling to allow trains to pass each other.
Operation
An example in Victoria: at Emu. Here there is left hand side running through the loop. The train driver approaching the loop sees the yellow arrow to show the points are set correctly for a cross.
Sulky Loop had right hand running: here the train has thrown the points over to exit the loop, so the two red dots indicate an approaching train cannot enter the loop for a cross (kinda obvious, it is more for if the points do not restore correctly).
A closer view of the equipment, at Heywood:
Reverse view, this time at Warrenheip:
Self-restoring mechanism and point indicator, at Emu Loop:
The train moves towards them, the point blades are always held to one side by what is called a Mechanical Switchman - it is basically a hydraulic piston with a delay:
A train proceeding in the opposite direction will force the point blades out of the way, the mechanical switchman will move the blades back to the normal position a short time after the train has passed.
In short trailable points it is a cheap way to provide a crossing loop, you don't need to install signalling or point motors, and you don't need the train crew to get out of the loco to change the points. The bad part is the speed restriction through them: in Victoria it is 40 km/h.
At some locations such as such as Emu, Sulky, and Glenthomson an electric point indicator (ie signal) was provided. G/Y for set points, Y/Y for not set. This was due to the curved approach making it difficult for train crews to see the indicator at the points until too late.
Speed limits
Trains passing over trailable points are subject to the following speed restrictions until the Train has cleared all facing and trailing points:
- 40 km/h when running to or from lines diverging from the straight track
- 80 km/h over facing trailable points, when running on the straight track
- 65 km/h over trailing trailable points until locomotives clears points, when running on the straight track
- 80 km/h over trailing trailable points AFTER locomotives clears points, when running on the straight track
Usage
The three major applications of single line sections with trailable crossing loops in Victoria were installed in the 1980s:
- North Geelong to Mildura via Ballarat, still in use today
- Maroona to Portland, still in use today
- Gheringhap to Maroona, prior to standardisation in 1995
The trailable loops on the Mildura line were set up generally so that Down trains are routed via the loop road and Up trains via the straight road, so that loaded grain trains would have reduced travel times and fewer diverging moves.
Today's V/Line doesn't like running passenger trains through trailable crossing loops, so the loops at Sulky, Tourello and Talbot were removed before passenger trains resumed to Maryborough in 2010.
ARTC rulebook
From TA20 – ARTC Code of Practice for the Victorian Main Line Operations:
13. Trailable Points At Unattended Crossing Station/Loopsa. Operation of Trailable Points
Trailable plunger locked facing points are locked mechanically for facing movements.
For trailing movements the points are automatically unlocked and thrown to the reverse position by the wheel flanges of the passing train.
After the train has passed, the mechanical switchman pulls the points back to normal and by means of a weight and crank system attached to the plunger, the points are automatically locked ready for the next facing or trailing movement.
Where trailable points are provided at single line crossing loops, the points at each end of the crossing loop normally lie for the left-hand track, applicable to trains approaching the facing points. At some locations however the points at each end may be set for the right-hand track.
b. Ground Lever for Shunting
A ground lever is provided at each set of trailable points. The lever is secured with a V5PSW padlock and is used for the operation of the points during shunting movements.
A switch stand is fixed adjacent to the main line points to indicate to approaching train crews the position of points.
c. Straight Track
The indications displayed on the switch stand are as follows:
'For Arriving Trains'
When the left or right hand track is the straight track and the points are normal and locked: two reflective green discs, or a reflective green fishtailed arrow pointing in the direction in which the points are set.
d. Diverging Track
When the left or right hand track is the diverging track and the points are normal and locked: two reflective yellow discs, or a reflective yellow fishtailed arrow pointing in the direction in which the points are set.
When the points are not correctly locked: two reflective red discs.
'For trailing movements' - two white discs with vertical black bars, or a white fishtailed arrow with vertical black bars or two white discs with horizontal black bar.
e. Points Unset for Trailing Movement
If, when approaching the points in the trailing direction, the Driver observes two white discs with horizontal black bars displayed on the switch stand, the Driver may proceed through the trailing points; but must immediately advise the Train Controller by train to base radio.
The Train Controller, upon being advised by the Driver that the two white discs with horizontal black bars are displayed on the switch stand, must immediately advise the Signals and Communications Supervisor for the area.
f. Two Red Discs Displayed for Facing Movement
In the event of two red discs being displayed for an arriving train, the Driver must stop the train on the approach side of the points and examine the closed blade of the points for any obstruction.
The point lever must then be unlocked and the points reversed and further examination made for any stones, or other foreign material between the blade and the stock rail. The lever is then to be restored to 'Normal' and if the indicator still does not respond to the lever and the points are in the correct position, the lever should be locked and the train may proceed.
The Train Controller must be immediately informed of the defect. The Train Controller must then inform the Signals and Communications Supervisor for the area.
Where the Driver is accompanied by a competent employee, the competent employee will be responsible for examining the points.
NOTE:
The points may be run through in the trailing direction, but care must be taken to ensure that all vehicles are clear of the points before the direction of the movement is reversed.
However, if the ground lever is placed in the correct position for the intended facing movement prior to the vehicles engaging the points in the trailing movement, it will not be necessary for all vehicles to clear the points before setting back.
The operation of these points differ from that of CCW points in that the operation of the trailable points ground lever is not effective whilst vehicles are standing on the points.
g. Shunting Movements
For shunting movements, the points may be set for either track by means of the ground lever.
During the shunting operation, the Driver of the movement shall control the movement in accordance with the indication displayed on the Switch Stand. The display of 2 Red Discs shall indicate to the Driver that the movement is proceeding over the facing points in the wrong direction and the speed of the movement shall be controlled as directed by the competent employee performing the shunt operations on the ground.
When the shunting is completed, the points shall be set in the `Normal' position and the lever locked with the V5PSW padlock. The Switch Stand shall also be inspected to ensure it is displaying the correct indication.
Sources
- TA20 – ARTC Code of Practice for the Victorian Main Line Operations (4 October 2015)
- V/Line Network Service Plan: North Geelong to Yelta (12 October 2016 )