Busy days on the railway usually see us sailing up and down the line, under the watchful eyes of the signalmen at Sheringham, Weybourne and sometimes Holt as well. Less busy days might see the Weybourne and Holt signal boxes unmanned (or 'locked out') and the railway controlled by the 'One Train on Line' method. On these days, the run around at the end of the line involves the guard operating the points and signals at Holt from the ground frame.
Today, a group of us, mostly guards plus me from Steam Locomotive Operations were engaged in a refresher course on point operation by Stuart, one of the railway's Responsible Officers. The purpose of the course was to remind the assembled group on how points were operated in the event of power failure or other faults.
At Holt, Weybourne and Sheringham most of the points are electrically operated from the signal box or ground frame by an electrical point motor:
That roundish bit in the foreground is the motor; the rectangular box in the middle houses the reduction gears and the rack & pinion used to convert rotary motion into linear, to move the point blades:
At the far end, the square box houses the switches which tell the signalman the point has reached the end position successfully (or not...)
There are two bars passing through this box from left to right in the picture - both are attached to the point blades. The lower one operates the limit switches, and the upper one is provided with cut-out sections which mesh the a third bar, passing through the box from top to bottom - this is the 'facing point lock'.
The picture above shows the various rods connecting the switch box, locking bar and point motor to the moving blades.
The facing point lock bar can be seen emerging from the end of the point motor. This one is unlocked:
Manual and electric points operated from the signal box feature three stages of operation - unlocking the blade, movement of the blade, and locking the blade again. In the signal box a manual point is operated by a black lever, and locked with a blue lever - the lock prevents the blades moving under the pressure from the train. An electric point is operated from one lever which is painted blue and black.
When operating an electrical point, or manually winding it, roughly one third of the movement unlocks the point; the second third moves the blades, and the final third locks the point again. When manually winding the point you can feel the weight of the blades in the middle third of the movement.
An electric point is manually wound using a lever which may be obtained from the associated signal box or ground frame. It is used in a square socket (almost square actually), hidden under a padlocked cover on top of the motor. Loco crew members should have the key with them!
To wind the point, the red painted lug needs to be moved out of the way of the lever socket - moving this lug disconnects the supply from the point motor. When the lever has been inserted, winding the point is straightforward though it must be remembered to wind the lever until it stops such that the point is properly unlocked, moved, and locked again:
When the movement is complete, the lug is re-positioned and the supply reconnected by grasping the reset knob, pulling it out and pushing it in again:
It should be noted that if the point is being hand wound through reasons of power failure, it is not unlikely that the failure may extend to the whole ground frame. If that is the case, the ground frame cannot be operated, which means the signals cannot be operated either.
In this event, the matter is significantly more serious since signals will prevent the train movement. The Responsible Officer must be called for permission to pass signals at danger; in practice, any failure should be reported. The RO will provide permission for the movement to take place if it is safe to do so but it is likely that several permissions will be required for the movement so it is wise to keep the phone line open until the whole run-around is completed. It should be noted that these are safety critical communications and written procedures apply.
A word on hand points:
A hand point, operated from a lever beside the point, can be driven through in the trailing direction, which will change the state of the points.
To fix the state of a hand point, clipping and scotching is used which holds both moving blades in a given position, removing any risk of derailment or preventing a route being set.
Today, a group of us, mostly guards plus me from Steam Locomotive Operations were engaged in a refresher course on point operation by Stuart, one of the railway's Responsible Officers. The purpose of the course was to remind the assembled group on how points were operated in the event of power failure or other faults.
At Holt, Weybourne and Sheringham most of the points are electrically operated from the signal box or ground frame by an electrical point motor:
That roundish bit in the foreground is the motor; the rectangular box in the middle houses the reduction gears and the rack & pinion used to convert rotary motion into linear, to move the point blades:
At the far end, the square box houses the switches which tell the signalman the point has reached the end position successfully (or not...)
There are two bars passing through this box from left to right in the picture - both are attached to the point blades. The lower one operates the limit switches, and the upper one is provided with cut-out sections which mesh the a third bar, passing through the box from top to bottom - this is the 'facing point lock'.
The picture above shows the various rods connecting the switch box, locking bar and point motor to the moving blades.
The facing point lock bar can be seen emerging from the end of the point motor. This one is unlocked:
Manual and electric points operated from the signal box feature three stages of operation - unlocking the blade, movement of the blade, and locking the blade again. In the signal box a manual point is operated by a black lever, and locked with a blue lever - the lock prevents the blades moving under the pressure from the train. An electric point is operated from one lever which is painted blue and black.
When operating an electrical point, or manually winding it, roughly one third of the movement unlocks the point; the second third moves the blades, and the final third locks the point again. When manually winding the point you can feel the weight of the blades in the middle third of the movement.
An electric point is manually wound using a lever which may be obtained from the associated signal box or ground frame. It is used in a square socket (almost square actually), hidden under a padlocked cover on top of the motor. Loco crew members should have the key with them!
To wind the point, the red painted lug needs to be moved out of the way of the lever socket - moving this lug disconnects the supply from the point motor. When the lever has been inserted, winding the point is straightforward though it must be remembered to wind the lever until it stops such that the point is properly unlocked, moved, and locked again:
When the movement is complete, the lug is re-positioned and the supply reconnected by grasping the reset knob, pulling it out and pushing it in again:
It should be noted that if the point is being hand wound through reasons of power failure, it is not unlikely that the failure may extend to the whole ground frame. If that is the case, the ground frame cannot be operated, which means the signals cannot be operated either.
In this event, the matter is significantly more serious since signals will prevent the train movement. The Responsible Officer must be called for permission to pass signals at danger; in practice, any failure should be reported. The RO will provide permission for the movement to take place if it is safe to do so but it is likely that several permissions will be required for the movement so it is wise to keep the phone line open until the whole run-around is completed. It should be noted that these are safety critical communications and written procedures apply.
A word on hand points:
A hand point, operated from a lever beside the point, can be driven through in the trailing direction, which will change the state of the points.
To fix the state of a hand point, clipping and scotching is used which holds both moving blades in a given position, removing any risk of derailment or preventing a route being set.
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