Is it OK to place signals in tunnels?

XPTE · Post by **XPTE** » Fri Nov 21, 2003 3:30 pm

Is it OK to place signals in tunnels? Or would this cause any problems?

pepsipowell · Post by **pepsipowell** » Fri Nov 21, 2003 4:38 pm

I think the Albula line had signals in tunnels, and as far as I know it shouldn't cause problems (apart from being a little harder to place in RE!). Can anyone confirm this?

Jonathan

asalmon · Post by **asalmon** » Fri Nov 21, 2003 4:42 pm

I have seen several routes with signals inside tunnels.

GOK how you get them there!!

Alan

jjules · Post by **jjules** » Fri Nov 21, 2003 4:42 pm

It's an interesting idea...Quite why it would be necessary for signals to be placed inside a tunnel baffles me though. Unless you've got a junction inside the tunnel, which would be complicated...

Blaster · Post by **Blaster** » Fri Nov 21, 2003 4:43 pm

Yes the Albula line has signals placed inside tunnels.And like you say it makes it that little bit more awkward to place that is all.
Phil

barrymcguire9999 · Post by **barrymcguire9999** » Fri Nov 21, 2003 4:53 pm

Placing signals in tunnels is not a problem (apparently problems can arise if you then bury the tunnel under terrain so I just bury the start and end of tunnels under terrain.). I have put plenty of signals in tunnels on my Merseyrail Electrics route........(may be released at some point....)

Cheers

Barry

XPTE · Post by **XPTE** » Fri Nov 21, 2003 4:55 pm

jjules wrote:It's an interesting idea...Quite why it would be necessary for signals to be placed inside a tunnel baffles me though. Unless you've got a junction inside the tunnel, which would be complicated...

I went on the Severn Beach line yesterday, and was surprised to find that there were 2 signals in Clifton Down Tunnel for Southbound trains. So I made a note of these and thought I will have to put these signals into my version of the route.

jjules · Post by **jjules** » Fri Nov 21, 2003 5:01 pm

Ah! Fair enough then. I didn't know there was a thing being done, as I've never seen it.

XPTE · Post by **XPTE** » Fri Nov 21, 2003 6:19 pm

Well I've just tried to place a signal in the tunnel and apparantly it's not possible. Because the top of the signal sticks out of the tunnel roof! The standard signals fit in there allright, but not the ones with feather indicators - which is what I need to use as there's a junction just outside of the tunnel.

Hmmm..... I think I'll place the signals just before and just out of the tunnel instead.

terrycunliffe · Post by **terrycunliffe** » Fri Nov 21, 2003 6:19 pm

Tried it in the NWE Lime street tunnels, no problem with the positioning and functioning of the signals, it's just that I couldn't get them to look right... So in the end, I didn't bother...
Terry

XPTE · Post by **XPTE** » Fri Nov 21, 2003 6:20 pm

Well I've just tried to place a signal in the tunnel and apparantly it's not possible. Because the top of the signal sticks out of the tunnel roof! The standard signals fit in there allright, but not the ones with feather indicators - which is what I need to use as there's a junction just outside of the tunnel.

Hmmm..... I think I'll place the signals just before and just out of the tunnel instead.

terrycunliffe · Post by **terrycunliffe** » Fri Nov 21, 2003 6:25 pm

XPTE wrote:Well I've just tried to place a signal in the tunnel and apparantly it's not possible. Because the top of the signal sticks out of the tunnel roof! The standard signals fit in there allright, but not the ones with feather indicators - which is what I need to use as there's a junction just outside of the tunnel.

Hmmm..... I think I'll place the signals just before and just out of the tunnel instead.

I tried using the "gantry" signals (without the gantry, of course!)... would fit inside the tunnel a-ok, it just looked strange..
Terry

Cobos · Post by **Cobos** » Fri Nov 21, 2003 6:52 pm

Simply use the signal heads only. Place them just above the ballast and angle them slightly backwards. Looks just the ticket, as most signals in tunnels are at ground level, I believe.

Kerr

terrycunliffe · Post by **terrycunliffe** » Fri Nov 21, 2003 7:07 pm

Cobos wrote:Simply use the signal heads only. Place them just above the ballast and angle them slightly backwards. Looks just the ticket, as most signals in tunnels are at ground level, I believe.

Kerr

Now, why didn't I think of that?

I was trying to use the signal heads 'suspended' from the tunnel roof...
Terry

simont · Post by **simont** » Fri Nov 21, 2003 7:15 pm

It's an interesting idea...Quite why it would be necessary for signals to be placed inside a tunnel baffles me though. Unless you've got a junction inside the tunnel, which would be complicated...

Well, the closer on a line signals are together, the more capacity there is. If you have a long tunnel with no signal in, you have a longer block section, so if there's a train in the tunnel, anything directly behind it will have to wait untill it's come out the other end. A signal in the tunnel means it's broken into two block sections, so you can have two trains in the tunnel going in the same direction at the same time.

A good example of this is the Channel Tunnel, which of course has several signals.