New short siding at Howth Junction

highdef

Hi
I was just wondering if anyone knows what the very short siding which is in the process of being fitted on the southbound track on platform 1 (or is it 4?) just at the western end of the platform and just before the junction itself. The siding itself only appears to be 20 or 30 foot long and it has not yet been connected to the main track. The siding is being electrified too and a rather large and permanent looking pole supporting the overhead catenary has been installed. I'm presuming there's more to this siding than meets the eye. Any ideas? Enterprise, do you know?

MarkoP11

The siding is present to provide what is known as a trap point to stop a train passing a red signal at the end of the platform from entering the main line to Dublin.

As it stands a train is not allowed enter Howth Junction station if the route onto the main line is not clear, if a train where to pass the red signal currently it would be on a collision course with trains oncoming from Malahide. At the moment Darts have to be held at a signal some distance away from Howth Junction to prevent a possible collision

With this siding it will be possible to enter Howth Junction station on a red signal if the train fails to stop it will be directed to the short siding. Since the Dart fleet is fitted with automatic train protection equipment the chances of passing a red signal are remote, but if it did happen it would be a little more than a walking pace

This will save a significant amount of time and improve punctuality

highdef

Thanks for that Marko. I was kinda thinking it was something to do with that alright. I get the train at Bayside and there have been many times where I would be sitting for what seems like an eternity half way between Bayside and Howth Junction. However, I have remembered times in the past where the train actually sits at Howth Junction while a freight train or Enterprise passes through. This was a few years ago (back in my college days) and I've only just started using public transport again in the last few months so haven't noticed this happening recently. It's odd that sometimes back then, the train would wait at Howth Junction and at other times would wait between Bayside and Howth Junction.
Slightly off topic but I've been having trouble accessing the P11 forums over the past couple of weeks. When I click on the forums, I'm brought to a page which tells me who is online and an option to search for posts. If I try search, there are no results. It's the same on internet explorer and Mozilla firefox.
(sorry for the diversion at the end) - Get the pun, diversion
Sorry for the terrible joke just there :rolleyes:

MarkoP11

highdef wrote:

However, I have remembered times in the past where the train actually sits at Howth Junction while a freight train or Enterprise passes through.

Seen that happen too, it is possiblewhat happens there is the DART arrives and is held by the signalman to allow the other through, you set a route for the Dart to Kilbarrack and hold the signal in Howth Junction at red confirm the train is halted and revoke the route

highdef wrote:

I've been having trouble accessing the P11 forums over the past couple of weeks. When I click on the forums, I'm brought to a page which tells me who is online and an option to search for posts. If I try search, there are no results. :

There was a patch a month ago when there where some troubles but thats all done
http://platform11.hyperboards3.com/index.cgi?action=search&sRecentPosts=1&sDispView=posts&sDispNumResults=10&sSortBy=date&submit=1 works for me. Try logging in that has a big difference in performance for some reason

highdef

I think I know what you mean. In the past, when stuck with a red on platform 1, the signal would also be red on platform 3 (the mainline southbound platform - I think I have platform numbers right). I would then see the signal change to amber or green on platform 3. I'd imagine in this case, the train approaching from the Belfast direction would be held at the signal just before Furnace's Bridge where the big housing developments are going up and would not be cleared to proceed until the signal at Howth Junction is clear or proceed with caution. Am I making any sense here?

With regards to the patch, I'll try it out at home. In work at the moment and am barred from accessing the forum (company policy thing). Come to think of it, I also have a habit of not logging in. I'll try that first when I get home.

Thanks again.

SeanW

One thing though - if this is trap point to catch runaway DARTs, why is it electrified? Surely if a DART ran into this trap point you'd want to bring the train to a halt?

Victor

To get the DART out again.

You'll notice in places where an over shoot is possible, e.g. sidings & junctions around Connolly that they are all electrified.

jlang

Sean, I presume an un-electrified siding would prevent the DART being able to get back out without outside assistance?

highdef

An if it does run in to the trap, what is the maximum speed the Dart could be traveling at? I reckon it wouldn't be more than about 5mph. Would the buffer stop the train at his speed?

MarkoP11

The DART unit would be at no more than 15kph (if the running release is engaged) typically little more than a walking pace once it got to within 200-300m of the red signal there would be a constant beep from the ATP console which would also be flashing in red. The on board ATP equipment take care of the brakes so regardless of what the driver tries the train will stay firmly within the limit. The chance of passing the signal is very very remote but still possible at the speeds involved stopping before the buffer stop should not be a problem.

Of course what if the ATP system is broken or disabled, if the trackside equipment fails you are stuck at 15-20kph if the isolation switch is used you are stuck at 30kph, use of the isolation switch triggers the radio to send the equivelent of a text message to the control centre