Tows

[Aictos]

Having a look though the sectional appendix for the London North Eastern area and in particular Woolmer Green, I've came across one term which I've never heard off and am wondering what it actually means?

TOWS 3 systems Welwyn South Tunnels
Cutting between tunnels,
Welwyn North tunnels.

TOWS must not be used when Woolmer Green emergency crossover is to be used.

What of earth does it mean please?

 

[Mojo]

Train Operated Warning System. I'm sure one of the P-Way guys can give more detail, but AIUI it's one of a number of systems to warn track workers of approaching trains.

This has a bit more information.

 

[Aictos]

A bit like they have at Kings Cross then in the Belle Isle area with the light showing and a bell ringing?

 

[Old Timer]

To add to Mojo's earlier answer, TOWS was installed on certain lines in areas where there was restricted sighting of approaching trains, normally due to curves.

The system dispenses with the need for lookoutmen as it is track circuit operated by approaching trains, It is switched on at the start and switched off at the end of work. The switches are either at the access point or at the ends of the restricted area.

I have tried on various occasions to get NR to agree to installing signalling controls into Interlockings that we have been working on so as to introduce TOWS into dangerous areas, but this has always been steadfastly refused as it costs money.

The system at Belle Isle is (was) always on and is not a TOWS system in the true sense.

 

[Trog]

I have tried on various occasions to get NR to agree to installing signalling controls into Interlockings that we have been working on so as to introduce TOWS into dangerous areas, but this has always been steadfastly refused as it costs money.

Its worse than that most of the TOWS systems we did have on the south end of the WCML have been removed when the line was resignalled. The one that is left at Kilsby and Crick to Watford Lodge, is a bit strange as safety systems go. In that the switches are in boxes locked with a 222/221 S&T key which the P Way are not supposed to have.

 

[DaveNewcastle]

There was a similar question on here a while ago, but from the other point of view - as a passenger who thought that the sounders were constantly active (apparently making their "eeee -- owwww" noise 24 / 7 !).
That question was based on the curving stretch of ECML around Grantshouses, just inside the Scottish border, where every passing train does exactly what its supposed to do - it triggers the TOWS.
Can't blame regular passengers for assuming that they're constantly on - its a bit like the fridge light you could believe is on 24 / 7 based on your observation that its always on, whenver you look!

 

[moggie]

Hello chaps - first post on this forum.

I think there are a number of reasons nowdays why the systems are frowned upon even where the signalling interlocking / lineside circuity is being renewed. No doubt price is a factor but considering all the other parafernalia specified these days I would not consider TOWS to be a significant contributor - especially with SSI technology. I think the main reason are;

Environmental - noise intrusion due to the constant 'safe' tone when switched on with no trains about so I'm led to believe.

No use (to a signalling tech) when there is a either a track circuit failure in the system or the pway if they need a trolley on one line for example that may lead to a track showing occupied to the signalling system.

By definition - TOWS tended to be specified in areas where lookout protection was difficult / impractical / dangerous due to sighting contraints. Probably now subject to a ban on Red Zone working - I recall we still had to have lookouts anyway - but fewer of them were required to see around the bends.

New and 'improved' technology - various new protection systems that do not use the signalling system to detect the approach of a train. On West Coast the recent resignalling projects have been provided with Staff Lockout systems to disable signalled routes in association with T2 style posessions. I'm not sure how much of the latter is currently used.

PS - still enjoying reading your words of wisdom OT

 

[67029]

I Have a vid on my channel explaning about TOWS


http://www.youtube.com/watch?v=UY6DdGr_Bv4

 

[Signalfixer123]

In response to Ajax 103's question(s) I might be able to shed some light on the TOWS through there.
I think the Sectional Appendix might be slighty out of step with reality in this location, but that can only be confirmed or disputed by the author of that document.
In reality, there is a TOWS system in the South(short) Tunnel which can be turned on/off at either end of the tunnel. There is a TOWS system in the North(Long) Tunnel which again can be turned on/off at either end. There is nothing in the cutting as I recall.
Some many years ago, there was to be an upgrade to the TOWS through there and switches, posts, Yodalarms and wiring were installed. right through to just South of Knebworth. Then Clapham happened and eventually most of the new wiring, which was not yet connected, got ripped out so the intention of having three TOWS systems through there died.
As for the comment about Woolmer Green Ground Frame, this ground frame is trailing to the normal direction of traffic and the most logical thing I can think of is that if the ground frame was being used for SLW on the Down Main, then the TOWS would not( in it's current configuration) give sufficient warning time for a train travelling wrong road.
Hope this helps.

 

[Aictos]

Thanks guys,

 

[Old Timer]

A lot of the emergency crossovers on the GN were only very basically interlocked into the signalling system. By this I mean that the signals were autos, with only a GF release in the box.

Even though the release could be given, the signals only replaced when the GF release was taken on the ground, so you could happily have trains whizzing up and down with the GF release open.

That was the case on the KX and Doncaster PSB areas in the 70s and 80s. Possibly alterations could have taken place as crossovers were renewed.

Obviously when they were removed there were only minimal interlocking alterations needed rather than a full blown mod to the geographical units.