Petone - Blocking

Blocking is 19th century technology that is used in the 21st century to protect track workers and also vehicles that may not operate track circuits. A signal is placed at Stop and a collar is placed on the switch to remind the signalman not to operate the switch.

(Right)  A politically incorrect collar.

Men on Line


19th Century Technology
Extract from report into Norton Fitzwarren (UK) accident (1890):

I am informed that many signalmen put one of their flag sticks in the spring catch of the signal levers of the line that is blocked to prevent their forgetting that a train is waiting to proceed and pulling off their signals of the line that is occuppied. I would suggest that a slide bar, a loop, a wedge or some othe mechanical contrivance marked "Train" Waiting" should be fixed to the levers in the cabin to do this, and prevent these levers from being pulled by mistake.

Quote taken from Red For Danger by L.T.C. Rolt.

The signal is placed at Stop and a collar placed on the switch. Points switches can also be collared.

The Rules
In the 25/11/2008 version of the Track Safety Rules protection of track workers was provided under Rule 918 Foul Time. The signalman may also have used Rule 909 Work within Station Limits and Sidings. In the Alternative Track Safety Rules, introduced just weeks before Petone Box closed, these were replaced with Rule 908 Blocking.

Other situations where blocking was used included holding a signal at Stop under Rule 905 Compulsory Stop Protection (when a Stop board was located next to a signal), when a vehicle did not reliably operate track circuits (Rule 914) or if a mis 60 was in effect.


(Above)  The signal has been placed at Stop and a collar placed on the switch. The collar reminds the signalman not to operate the switch.

Last Updated: Sunday 24th Nov 2013

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