Metrolink Turnaround Sidings Question

[markymark2000]

I am wondering if anyone can help with this. I note that Manchester Metrolink has the most strange turnaround sidings using only trailing points which mean that a tram which is changing directions must do so on a normal line, then head into the siding before joining the correct running line. What is the logic of this? Isn't the point of turnaround sidings that the tram can sit in the siding then the driver switches ends then heads back the same way? That operation increases capacity of the line as a tram isn't blocking a main line while the driver switches ends. The only benefit that I can see of Metrolink having their points and sidings in this way is that there is slightly less cost. Less points to build and maintain. Examples of these can be found on Warren Bruce Road in Trafford Park and between Velopark and Etihad Campus.

Wouldn't siding layouts such as those at Cornbrook (for the one near Etihad Campus) or Timperley (for the one at Warrn Bruce Road) make more sense for these areas?


Etihad Campus siding: https://www.google.co.uk/maps/@53.4835685,-2.1956162,140m/data=!3m1!1e3
Warren Bruce Road Siding: https://www.google.co.uk/maps/@53.4686708,-2.303983,114m/data=!3m1!1e3

 

[plugwash]

Looking at it from the other direction, it seems that a "tralling only turnaround siding" would be only marginally more expensive to build than a simple crossover and would provide a place for trams to wait for their scheduled return departure or a place that failing trams could be dumped.

Given the mostly line of sight operation and the short length of metrolink trams I doubt that blocking the line for the time it takes a driver to walk from one end to the other are a massive issue for metrolink.

 

[Mothball]

As both of those turnbacks are to facilitate football specials it would make sense that it's so the trams are stacked in the order they arrived. So if two trams are stabling up, the first one into the turnback will become the first one out. If the points were facing the first one in becomes blocked by the second.

 

[Cheshire Scot]

As both of those turnbacks are to facilitate football specials it would make sense that it's so the trams are stacked in the order they arrived. So if two trams are stabling up, the first one into the turnback will become the first one out. If the points were facing the first one in becomes blocked by the second.

The turnback to the east of Piccadilly station is entered through facing points.

 

[Mothball]

The turnback to the east of Piccadilly station is entered through facing points.

But only intended for in and out, quick turnarounds. Not queuing vehicles ready for a large rush of people.
The other advantage of the Velpoark and WBR turnbacks would theoretically allow one to enter from the rear while another prepares to leave the front.

 

[507 001]

As Mothball says, it’s to do with their intended use for football traffic.

As it happens, the plan is to reconfigure Velopark siding in a few years time as it has turned out to be operationally awkward due to how it’s situated.

Imperial War Museum however works much better as it’s actually a simplified version.

 

[markymark2000]

As Mothball says, it’s to do with their intended use for football traffic.

As it happens, the plan is to reconfigure Velopark siding in a few years time as it has turned out to be operationally awkward due to how it’s situated.

Would that be due to trams having to block the main line so that staff can switch ends?

Imperial War Museum however works much better as it’s actually a simplified version.

How is it more simple? It looks the exact same.

 

[tbtc]

Tsch, turn back sidings for these posh Mancunians, is it?

Here in Sheffield we expect to be able to reverse trams on the main line itself with nowhere for them to actually lay over, meaning the the Purple Line (pre-Covid frequency of half hourly from Herdings) and the Tram Train (pre Covid frequency of three/hour from Parkgate , on the far side of Rotherham, but lopsided because the three Northern DMUs through Rotherham weren’t well spaced) both officially have two minutes to arrive into Cathedral, driver change ends and resume the journey to the south/east, in between the combined blue/yellow service (was every five minutes pre Covid), so as you’ll imagine things often saw a queue of vehicles blocking the westbound line down High Street causing trams to be stuck from Park Square bridge since they couldn’t straddle the road junctions, as well as blocking part of Church Street eastbound

Same “reverse on the main line” applies at Sheffield station/ Arena (which certainly used to get as lot of dupes at big events)/ Shalesmoor/Hillsborough and various cross overs towards Halfway - these aren’t used for regular daytime reversals though

Sorry, i sound bitter, I’m just pointing out that a poor reversal siding is something we’d much prefer this side of the Pennines when compared to our own very “simple” track diagrams! Great is always greener, eh?

 

[edwin_m]

Tramway points that are only used in the trailing direction during normal operation don't need motors, and may not need detection and position indicators (they are operated by hand on the rare occasions that is needed). So tramway track designs tend to avoid facing points wherever possible, to avoid the extra cost and possible source of unreliability. I recall there were only nine motorised points on the entire Tramlink network for example.

 

[plugwash]

Do tramways still use "sprung points" such that a tram going in the "normal" direction goes straight through but a tram going in the reverse direction crosses over without needing to manually change the points?

 

[edwin_m]

Do tramways still use "sprung points" such that a tram going in the "normal" direction goes straight through but a tram going in the reverse direction crosses over without needing to manually change the points?

It's slightly more complicated than that, but in simple terms yes. However emergency crossovers normally lie for the through track, to avoid wearing the blade as every vehicle trailing through pushes it out of the way. They can be reversed manually if required, and in either setting are trailable from the other route. Last time I looked closely at the points in Piccadilly Gardens, the trailing one towards Mosley Street had a very noticeable wear patch, as in normal operation the blades are being pushed to and fro constantly.

 

[Crossover]

Do tramways still use "sprung points" such that a tram going in the "normal" direction goes straight through but a tram going in the reverse direction crosses over without needing to manually change the points?

On Metrolink, the approach to Rochdale Town Centre where outbound (towards Rochdale Town Centre) the track singles, the points are sprung. I have previously stood and watched the points detection flick from detected to not detected for an inbound move, as a tram passes over outbound and each set of bogies moves the points before they "snap" back to normal

 

[Starmill]

Tramways can also have 'up and over' crossovers, where there's a switch but instead of a traditional crossing being in place the wheel just rises up and goes over the top of the normal running rail. This obviously means that they're only suitable for a maximum of 5 miles / hour and may not be permitted for operation with passengers.

 

[edwin_m]

Tramways can also have 'up and over' crossovers, where there's a switch but instead of a traditional crossing being in place the wheel just rises up and goes over the top of the normal running rail. This obviously means that they're only suitable for a maximum of 5 miles / hour and may not be permitted for operation with passengers.

There are at least two of those in central Nottingham. To clarify, only the emergency crossing move goes "up and over", and the normal straight move is continuously supported with no flange gap, which presumably helps with noise and rail wear.

 

[507 001]

Would that be due to trams having to block the main line so that staff can switch ends?


How is it more simple? It looks the exact same.

First point, yes, it can cause slight delays on the Ashton line in its current form.

Second point, IWM is much simpler in the sense that it isn't signalled and all of the points are manually operated. Need to use it on a football day? First set swings the points, and they then operate as spring return until the last set enters the siding. The driver of the last set then normalises the points.

Velopark on the other hand is fully signalled, with motored points. It also has the system's only reverse PPI, which has been known to cause confusion in the past. In short it's a pain in the arse.

Tsch, turn back sidings for these posh Mancunians, is it?

Here in Sheffield we expect to be able to reverse trams on the main line itself with nowhere for them to actually lay over, meaning the the Purple Line (pre-Covid frequency of half hourly from Herdings) and the Tram Train (pre Covid frequency of three/hour from Parkgate , on the far side of Rotherham, but lopsided because the three Northern DMUs through Rotherham weren’t well spaced) both officially have two minutes to arrive into Cathedral, driver change ends and resume the journey to the south/east, in between the combined blue/yellow service (was every five minutes pre Covid), so as you’ll imagine things often saw a queue of vehicles blocking the westbound line down High Street causing trams to be stuck from Park Square bridge since they couldn’t straddle the road junctions, as well as blocking part of Church Street eastbound

Same “reverse on the main line” applies at Sheffield station/ Arena (which certainly used to get as lot of dupes at big events)/ Shalesmoor/Hillsborough and various cross overs towards Halfway - these aren’t used for regular daytime reversals though

Sorry, i sound bitter, I’m just pointing out that a poor reversal siding is something we’d much prefer this side of the Pennines when compared to our own very “simple” track diagrams! Great is always greener, eh?

We have plenty of standard crossovers too. The more heavily used ones, usually those that are at timetabled termini, are sidings.

Tramway points that are only used in the trailing direction during normal operation don't need motors, and may not need detection and position indicators (they are operated by hand on the rare occasions that is needed). So tramway track designs tend to avoid facing points wherever possible, to avoid the extra cost and possible source of unreliability. I recall there were only nine motorised points on the entire Tramlink network for example.

Quite a lot of ours are still motorised, and most have PPIs on them to allow use with passengers on.

Tramways can also have 'up and over' crossovers, where there's a switch but instead of a traditional crossing being in place the wheel just rises up and goes over the top of the normal running rail. This obviously means that they're only suitable for a maximum of 5 miles / hour and may not be permitted for operation with passengers.

We only have one of those, Aytoun Street emergency turn back. It's very, very rarely used however.

 

[markymark2000]

First point, yes, it can cause slight delays on the Ashton line in its current form.

Second point, IWM is much simpler in the sense that it isn't signalled and all of the points are manually operated. Need to use it on a football day? First set swings the points, and they then operate as spring return until the last set enters the siding. The driver of the last set then normalises the points.

Velopark on the other hand is fully signalled, with motored points. It also has the system's only reverse PPI, which has been known to cause confusion in the past. In short it's a pain in the arse.

Ahh, interesting. Thank you. I suppose the IWM ones wouldn't cause as much issue either with the lower frequencies on the Trafford Park line in comparison to Ashton line which is much busier.

Makes much more sense so thank you for your replies.

 

[507 001]

Ahh, interesting. Thank you. I suppose the IWM ones wouldn't cause as much issue either with the lower frequencies on the Trafford Park line in comparison to Ashton line which is much busier.

Makes much more sense so thank you for your replies.

The frequency of both lines is the same. The reason the Ashton one has to be signalled is due to the curve at the top of the hill.

 

[markymark2000]

The frequency of both lines is the same. The reason the Ashton one has to be signalled is due to the curve at the top of the hill.

Ashton went to every 6 mins didn't it?

 

[507 001]

Ashton went to every 6 mins didn't it?

It did for a short time pre-covid. It hasn’t returned to that level, and is unlikely to for some time.

 

[Crossover]

Tramways can also have 'up and over' crossovers, where there's a switch but instead of a traditional crossing being in place the wheel just rises up and goes over the top of the normal running rail. This obviously means that they're only suitable for a maximum of 5 miles / hour and may not be permitted for operation with passengers.

We only have one of those, Aytoun Street emergency turn back. It's very, very rarely used however.

When I read @Starmill's post, I had a feeling that was one on the Metrolink network.

For anyone interested, here is the Streetview, where the "up and over" is quite clear!

Google Maps

Find local businesses, view maps and get driving directions in Google Maps.

goo.gl

 

[507 001]

When I read @Starmill's post, I had a feeling that was one on the Metrolink network.

For anyone interested, here is the Streetview, where the "up and over" is quite clear!

Google Maps

Find local businesses, view maps and get driving directions in Google Maps.

goo.gl

It’s worth pointing out that we avoid up and overs at Metrolink. The only reason this is one is due to noise complaints. It wasn’t one originally.

 

[Crossover]

It’s worth pointing out that we avoid up and overs at Metrolink. The only reason this is one is due to noise complaints. It wasn’t one originally.

Presumably complaints of noise of sprung points?

 

[507 001]

Presumably complaints of noise of sprung points?

No, the noise as wheels pass over the crossing part of the points.

 

[MCR247]

There are at least two of those in central Nottingham. To clarify, only the emergency crossing move goes "up and over", and the normal straight move is continuously supported with no flange gap, which presumably helps with noise and rail wear.

Is this the royal centre and market square?

 

[edwin_m]

Is this the royal centre and market square?

Yes.

 

[MCR247]

Yes.

Thanks, I assumed so

 

[py_megapixel]

I spotted a tram from Didsbury terminating at Firswood at about 19:15 on Friday. I think it departed Firswood empty towards the city.

Anyone have any idea where it went next? Did it turn round somewhere and head back to Didsbury or the Airport?

 

[Mothball]

I spotted a tram from Didsbury terminating at Firswood at about 19:15 on Friday. I think it departed Firswood empty towards the city.

Anyone have any idea where it went next? Did it turn round somewhere and head back to Didsbury or the Airport?

It will have ran into Trafford depot.

 

[507 001]

I spotted a tram from Didsbury terminating at Firswood at about 19:15 on Friday. I think it departed Firswood empty towards the city.

Anyone have any idea where it went next? Did it turn round somewhere and head back to Didsbury or the Airport?

One of the peak extras coming in to Trafford Depot.