Wednesday 30 March 2022

Detector Fitting

 Tuesday 29th March

A bit more work to do on the new crossover at Toddington today. The connections to the points (14) and their  FPL (nearest the station) have not been made yet and are clipped for the road from platform 1 to the main line south. 

Our main objective today was to fit the detection unit for this point

Firstly, a concrete base is prepared using wooden shuttering:


The detector has four securing bolts (note the blue nuts) which have had a short bar welded on to the head. We then lifted the unit into position and sank the bolts into the wet concrete. We will tighten the nuts  next week when the concrete has set.


There is a slotted bar which passes through the centre of the unit (aligned with and parallel to the signal wire seen on top). The signal wire which connects to the adjacent ground signal now has to be cut and attached to each end of the bar.

Only if the slots in the three bars connected to the point blades and FPL coincide with the slot in the detector can the signal be operated. This next picture gives a better view of the arrangement


The FPL in the centre of the photo is not yet connected to the angle crank (on the 3rd sleeper to the right). To ensure that there is no relative movement between them and to prevent misalignment, the sleepers are strapped together with a steel strap on both sides:



And finally a bit of ground signal refreshment. Replacement of the two discs on the unit by the bracket signal - beautifully hand painted by Malcolm W!


Despite the weather - raining heavily in the morning - we achieved our objectives and the concrete escaped the downpour!

Curly



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