What are these?

[TTA]

I see these often near platforms - I've always wondered what they are?

If I were to guess, given it has electric power - is it some way to tell if a train is in a platform block?

 

[R G NOW.]

View attachment 59343

I see these often near platforms - I've always wondered what they are?

If I were to guess, given it has electric power - is it some way to tell if a train is in a platform block?

I would say a modern style Automatic Warning System ramp.

 

[LowLevel]

It's an automatic warning system (AWS) ramp. It's an electromagnet which sends a signal to a receiver on a train. This activates a horn or chime in the cab to indicate if a signal is showing a clear or restrictive aspect or to emphasise an upcoming speed restriction. It also operates a visual 'sunflower' display for the driver.

When energised you get a ping or a ring and the sunflower turns black.

When not energised you get a warning horn and the sunflower turns black and yellow.

 

[AM9]

An uncoupling magnet?

 

[TTA]

It's an automatic warning system (AWS) ramp. It's an electromagnet which sends a signal to a receiver on a train. This activates a horn or chime in the cab to indicate if a signal is showing a clear or restrictive aspect or to emphasise an upcoming speed restriction. It also operates a visual 'sunflower' display for the driver.

Cool - more interesting than I thought then!

 

[Elecman]

Bi Directional AWS unit

 

[whhistle]

An uncoupling magnet?

:P
Needs a like button.

Funny how Hornby decided to make them very similar though.
I wonder if that was to help them blend in?

 

[rich r]

The one in the photo looks unusual because it's not black, covered in oil and toilet effluent

 

[sw1ller]

How many mainline colour light signals are there in the uk that do NOT have these fitted? I can think of one. Just wondered how unique it is.

 

[DarloRich]

is it a datum plate?

EDIT - poor joke. It is an AWS magnet as above!

 

[Llama]

I can think of three colour light signals on a running line that are not fitted with AWS within ten miles of where I am sat, and another one on a line closed in 2009.

 

[swt_passenger]

Are there differences between the yellow and green versions?

 

[sw1ller]

I can think of three colour light signals on a running line that are not fitted with AWS within ten miles of where I am sat, and another one on a line closed in 2009.

Really. Not quite as unique as I was told then. Fair enough.

 

[Llama]

All three (and the closed line one) are on single lines, I can't think of any without AWS on a unidirectional running line, apart from on goods lines.

 

[LowLevel]

The main examples on passenger lines not fitted with AWS tend to be major stations with complex trackwork and low speeds like Birmingham New Street. Derby didn't have it until it was resignalled last year.

 

[ComUtoR]

I can think of some at a major London terminal but out on the line I'd have to really push my route knowledge to remember where the others are located.

 

[Ken H]

Are there differences between the yellow and green versions?

I think the green ones are used on 3rd rail lines and have more powerful magnets to over come the magnetism induced by the large currents in the low voltage DC circuits.

 

[swt_passenger]

I think the green ones are used on 3rd rail lines and have more powerful magnets to over come the magnetism induced by the large currents in the low voltage DC circuits.

Thanks, that makes sense, and now you mention it the green ones are definitely a southern area thing aren’t they. I should have realised that...

 

[Tomnick]

How many mainline colour light signals are there in the uk that do NOT have these fitted? I can think of one. Just wondered how unique it is.

As well as @LowLevel ’s examples in AWS gaps at some major stations...

Colour-light section signals and IB home signals on absolute block lines often (? - certainly not always) tend to have no AWS.

‘SIMBIDS’ installations also tended to not have AWS in the wrong direction, if I’m not mistaken?

The example pictured is more unusual in that, as someone’s already noted above, it’s effectively performing the function of two AWS magnets, one in each direction - there’s two electromagnets, one on each side of the permanent magnet.

 

[Ken H]

As well as @LowLevel ’s examples in AWS gaps at some major stations...

Colour-light section signals and IB home signals on absolute block lines often (? - certainly not always) tend to have no AWS.

‘SIMBIDS’ installations also tended to not have AWS in the wrong direction, if I’m not mistaken?

The example pictured is more unusual in that, as someone’s already noted above, it’s effectively performing the function of two AWS magnets, one in each direction - there’s two electromagnets, one on each side of the permanent magnet.

Are there not round signs with AWS with a red cross through it at the end of AWS at the approach to big station, and the same sign without the cross when AWS starts again? Quite small on 1 foot high posts - sort of level with shunt signals.

As this example is on a bi-directional line maybe the same permanent magnet is used for 2 signals, one for each way. or maybe there is a magnet to suppress the AWS indication in the cab when the signal the AWS magnet is for is for the opposite direction the train is travelling in.

 

[sw1ller]

Well the only one I can think of on a main running line is Beeston Castles section on the down line between Crewe and Chester. It’s on a 90mph section but it’s very soon after a 75mph so you’d not be doing 90. I was told it’s rather unique.

AWS gaps at major stations I wasn’t counting as they’re a given. And the emergency signals near RAF Valley don’t count either as they’re not normally showing an aspect.

Sorry to take the thread off on a tangent, the question was answered fairly promptly so I thought I’d ask my question here too.

 

[Llama]

Is that section signal at Beeston Castle still two aspect after a semaphore outer and inner home?

All the signals I was thinking of are two aspect, in TCB signalling with full braking distances from the signals in rear, but all are on single lines.

 

[Tomnick]

Well the only one I can think of on a main running line is Beeston Castles section on the down line between Crewe and Chester. It’s on a 90mph section but it’s very soon after a 75mph so you’d not be doing 90. I was told it’s rather unique.

AWS gaps at major stations I wasn’t counting as they’re a given. And the emergency signals near RAF Valley don’t count either as they’re not normally showing an aspect.

Sorry to take the thread off on a tangent, the question was answered fairly promptly so I thought I’d ask my question here too.

It’s an interesting aside, so thanks for asking! It’s 90 past the IB homes in each direction at Bamford on the Hope Valley, and 90 at the distant (which does have a magnet of course) reducing to 85 at the home for Edale’s Up IB too, all those speeds easily and regularly achieved with 158s.

 

[Tomnick]

Are there not round signs with AWS with a red cross through it at the end of AWS at the approach to big station, and the same sign without the cross when AWS starts again? Quite small on 1 foot high posts - sort of level with shunt signals.

As this example is on a bi-directional line maybe the same permanent magnet is used for 2 signals, one for each way. or maybe there is a magnet to suppress the AWS indication in the cab when the signal the AWS magnet is for is for the opposite direction the train is travelling in.

There are indeed signs to indicate the start and end of an AWS gap, seen here (on the ever useful Railsigns site).

In the example pictured, the same permanent magnet is used for both signals as you suggest, with an electromagnet on each side. A train approaching in either direction will first encounter an electromagnet which should be deenergised (but presumably would have no effect in any case), then a permanent magnet and electromagnet as usual.

 

[Ken H]

There are indeed signs to indicate the start and end of an AWS gap, seen here (on the ever useful Railsigns site).

In the example pictured, the same permanent magnet is used for both signals as you suggest, with an electromagnet on each side. A train approaching in either direction will first encounter an electromagnet which should be deenergised (but presumably would have no effect in any case), then a permanent magnet and electromagnet as usual.

Thanks for the railsigns link. I was wrong about the 'end of AWS gap' sign -its square, not round.

How do you now the pic is what you say, and not a suppressing magnet for a move in the opposite direction to the signal the AWS is for? Do they look different somehow, or do you know the location? (So i know for next time i see one)

 

[alxndr]

The power going to them is to energise the electromagnets when the signal is at green. These are the bits next to the grey ramps at either end in the photo. The central block is the permenant magnet. The electro and permenant magnets give the opposite polarity to each other so that the on-board equipment can detect which it is picking up and thus whether the signal it is approaching is at green or not.

On some bidirectional lines, if there is not a signal facing the other way in the right location to share a permenant magnet it will also be fitted with a suppressor to "kill" the magnetic field produced by the permanent magnet when a route is set over the wrong direction for the magnet and avoid random alarms.

I think the green ones are used on 3rd rail lines and have more powerful magnets to over come the magnetism induced by the large currents in the low voltage DC circuits.

Green coloured magnets found around 3rd rail are energised with either 24 or 48V whereas the standard yellow magnets are 12 or 24V.

 

[61653 HTAFC]

is it a datum plate?

EDIT - poor joke. It is an AWS magnet as above!

You weren't the only one who clicked on the thread expecting to see a photo of a datum plate!

 

[Tim M]

More information on AWS will be found here. When you get to the ‘Strowger-Hudd’ section, click on the link to the Harrow and Wealdstone accident, very sobering reading but it is important to understand why such systems were introduced.
https://en.m.wikipedia.org/wiki/Automatic_Warning_System

 

[Ken H]

What was appalling about AWS installation was the failure of the then Southern Region to get AWS installed on 3rd rail lines, so SR trains were running without this basic safety gear while the rest of the system was busy installing.

Over the years we have give signallers more and more protection from mistakes while drivers had nothing. AWS made passing signals harder, and later missing speed restrictions harder too. Good news for drivers (and passengers)

Perhaps a present day driver could say how they would feel about driving in bad weather at night without AWS. Especially in semaphore signalled areas.

 

[Tim M]

What was appalling about AWS installation was the failure of the then Southern Region to get AWS installed on 3rd rail lines, so SR trains were running without this basic safety gear while the rest of the system was busy installing.

There were two issues with this:

1. A higher power AWS system was required to mitigate against the d.c. power from cross track traction current cables
2. The fact that, particularly in denser traffic areas on the approaches to London drivers would often be running to a succession of double yellow or even single yellow signal aspects. There were concerns about drivers being lulled into automatically cancelling the AWS and potentially doing so on the approach to red signals.

By the 1970’s ‘green’ higher power AWS magnets were available, and attitudes had changed to the double yellow issue. I believe London Bridge Resignalling in the mid/late 1970’s had AWS throughout, certainly the follow up scheme Victoria Area Resignalling was so equipped (I was heavily involved with that Contract), with other lines subject to their own installation programmes.