July 30 Quiz

[mrfs42]

I took the picture of the (I guess) stencil box as it rather grabbed my interest.

The first picture (the close up) shews 33¹/₃ or 125HZ. Now I understand the different frequencies, was this stencil box there to show that BOTH frequencies were present on the reversing siding?

If so, what does the blank top half of the theatre box show if either of the TC feeds drop?

[Chris M]

For ease of reference, here is the photograph again:

(click for a larger version)

[mrfs42]

Ta - I'm in a bit of technical blather at the mo, configuring the new laptop and getting moderately puzzled. Was too busy processing that to work out how to post a picture.

[Harsig]

Well it is not a stencil box. As far as I am aware it is an air valve usually used to control the train stop. The 33¹/₃ or 125HZ presumably indicates that this valve will operate on a supply of either frequency. This does not mean however that supplies of both frequencies will be in use at Wembley Park.

[Tom]

As Harsig says, it's a Glass Enclosed Valve that will work at either frequency (and pretty much anywhere between as it happens).

For the record, Wembley Park is a 125Hz area.

[Deleted]

Looks a bit ropey too, could do with being changed.

[mrfs42]

harsig said:

Well it is not a stencil box.

I thought it was unlikely, given the information that it conveys. Having said that, who would need to know this information? AETs?

harsig said:

As far as I am aware it is an air valve usually used to control the train stop.

As Tom calls this a 'Glass Enclosed Valve'; presumably this is to allow easy access in order to isolate the valve, without the business bits being open to all and sundry.

harsig said:

The 33¹/₃ or 125HZ presumably indicates that this valve will operate on a supply of either frequency. This does not mean however that supplies of both frequencies will be in use at Wembley Park.

Glad to see my suspicions that this is actually a 125Hz area, thank you all for your answers.