Detonator placers

[WillCav]

I've been researching Cheltenham Spa Malvern Road for a while and have found a picture of the West signal box (1908ish vintage) and there seems to be a fog man's hut just to the East with a single lever. By the hut is the inner distant first MalvRd East, but I assume lever is for the opposite line - outer distants for Lansdown Jn.

 

There is also detonator placers in the box which I think means two placers on the Down line very close to each other- one operated by signaller and one by fog man.

 

Does this sound feasible?

 

Thanks

 

Will

 

Edited August 10, 2021 by WillCav
Typo

[St. Simon]

Hi Will,

 

Just a thought off the top of my head, does the box switch out at night? So could the fog mans placer be for when there's fog but the box is closed?

 

I don't know the area, just a bit of of blue sky thinking?

 

Simon

[WillCav]

28 minutes ago, St. Simon said:

Hi Will,

 

Just a thought off the top of my head, does the box switch out at night? So could the fog mans placer be for when there's fog but the box is closed?

 

I don't know the area, just a bit of of blue sky thinking?

 

Simon

The box could switch out but only did 0800 Sun to 0400 Mon according to 1948 STT - it's definitely a thought.

 

Thanks

 

Will

[uax6]

I would have thought that the det placers operated from the box were only there for emergency use, not for general fogging duties.. 

 

Andy G

[5BarVT]

Hi Both,

They are related to different boxes. I wouldn’t want Malvern Rod West to have to monitor Lansdown’s distants and operate his dets in sympathy.  Safer to have a fogman watching the distant and the signalman getting on with his job.  Life would be busy enough having to apply the fog and falling snow regs with all the extra delays that come from that.

Paul.

 

[The Stationmaster]

16 hours ago, WillCav said:

I've been researching Cheltenham Spa Malvern Road for a while and have found a picture of the West signal box (1908ish vintage) and there seems to be a fog man's hut just to the East with a single lever. By the hut is the inner distant first MalvRd East, but I assume lever is for the opposite line - outer distants for Lansdown Jn.

 

There is also detonator placers in the box which I think means two placers on the Down line very close to each other- one operated by signaller and one by fog man.

 

Does this sound feasible?

 

Thanks

 

Will

 

Yes.  The Fogman's detonator placer and a signal box single shot detonator placer served totally different functions and neither was the substitute for the other.  But do look out to see if there was three shot detonator placer there as it would have been a possibility at Malvern Road station

[WillCav]

21 hours ago, The Stationmaster said:

Yes.  The Fogman's detonator placer and a signal box single shot detonator placer served totally different functions and neither was the substitute for the other.  But do look out to see if there was three shot detonator placer there as it would have been a possibility at Malvern Road station

Thanks Stationmaster,

 

I'm not sure I would know the difference between a regular and three shot placer, but I have found a good shot of where I think it is.

 

Crop of picture from 

https://thetransportlibrary.co.uk/index.php?route=product/search

I claim reasonable usage for research purposes but will happily delete picture if requested to.

 

I think the placer is next to the rear loco wheel - any idea what type it is?

 

Thanks

 

Will

[Michael Hodgson]

31 minutes ago, WillCav said:

Thanks Stationmaster,

 

I'm not sure I would know the difference between a regular and three shot placer, but I have found a good shot of where I think it is.

 

Many signal box worked emergency detonators actually have two detonators side by side.  This is because are so rarely used and the detonator is only replaced on a planned cycle or if it is actually used in emergency.  So a second one is provided as a backup to overcome the risk a single one might not go off when it is needed.

 

Picture of three shot detonator placer can be seen in the thread below.  These are rather further apart, so the driver would hear three distinct shots rather than two so close they combine into one bang.

 

Fogmen had to put a detonator on the rail/take it off according the aspect it is displaying at the time.  As distants were commonly fogged it was normal for a train to pass over and set off a detonator in fog because the distant is showing caution.  So fogmen tended to go through detonators rather faster and so their "fogging machines" had a magazine containing a supply of detonators and their machine is worked by a 3-position lever Off/On/Reload, whereas the signalman's single shot machine holds just the one and it only has two positions - on/off the rail.  Each time there is a single shot, the signalman has to go lineside and fix a replacement.

 

 

 

[The Stationmaster]

1 hour ago, WillCav said:

Thanks Stationmaster,

 

I'm not sure I would know the difference between a regular and three shot placer, but I have found a good shot of where I think it is.

 

Crop of picture from 

https://thetransportlibrary.co.uk/index.php?route=product/search

I claim reasonable usage for research purposes but will happily delete picture if requested to.

 

I think the placer is next to the rear loco wheel - any idea what type it is?

 

Thanks

 

Will

That's a standard Reading design single shot emergency detonator placer worked from a signal box.   Although it was called a single shot placer the piece tinplate which was inserted into the placer and actually held the dertionators had two detonators placed very close together so they exploded more or less simultaneously - in order to make a more noticeable bang/

 

Three shot placers were comparatively rare things and usually consisted of three of the type of placer seen above 'ganged together' several feet apart and operated by a single rod,  thus when something ran over them there were three distinctly separate 'bangs'.  They were most commonly used where an un-trapped bay line etc joined a running line but their use was not at all consistent.

[bécasse]

The two detonators in the so-called "single shot" detonator placers are so close together that the driver would hear only a single explosion. There used to be one on the line from Charing Cross at Borough Market Junction which worked automatically in accordance with the adjacent 4-aspect colour light (on the rails when red, off the rails for any other aspect) and on one occasion a train I was on ran over the detonators when they failed to withdraw when the aspect cleared. As may be imagined the driver pulled up pretty sharpish, but was shown a yellow flag by the bobby so the delay was minimal. Following trains would not have been so lucky as hand signalling would have been required until the lineman could replace the detonator-placer.

[Pandora]

26 minutes ago, bécasse said:

The two detonators in the so-called "single shot" detonator placers are so close together that the driver would hear only a single explosion. There used to be one on the line from Charing Cross at Borough Market Junction which worked automatically in accordance with the adjacent 4-aspect colour light (on the rails when red, off the rails for any other aspect) and on one occasion a train I was on ran over the detonators when they failed to withdraw when the aspect cleared. As may be imagined the driver pulled up pretty sharpish, but was shown a yellow flag by the bobby so the delay was minimal. Following trains would not have been so lucky as hand signalling would have been required until the lineman could replace the detonator-placer.

I recall the line and the det placer at London Bridge,  movements of engineers trains in possessions  used to regularly bang  the dets,  there was a det placer a New Cross station for L217 signal,   to protect a conflicting movement from the adjacent  L219 signal  over the crossing to the down slow when L217 at danger,  the overlap for L217 signal being only around 30 to 40 yards in length and not the full overlap  200m typical of the area, the det placer did save an incident in around 1998 or 1999, a driver pulled away against a red,  as a non-stopper  was running through the platform,  a side-swipe collision was prevented.   Schoolchildren would steal the dets or drop  bricks and set them off. The placer mechanism is still there but badly damaged, not being required after the resignalling of the area

Edited August 12, 2021 by Pandora