West Midlands Metro Tracklaying in Brum

[TheSignalEngineer]

On 16/09/2021 at 00:43, wombatofludham said:

but as with the almost paranoia about stray currents which our continental friends seemingly dismiss,

I'm not sure how much they dismiss it. Control of electrical interference is not a railway specific matter. The basic requirements are laid down in EN50121. Railway standards are developed to comply with this. 

My main involvements with immunisation of S&T equipment were Watfors DC Lines, Thameslink and Midland Metro.

Traction interference was suspected of causing problems on the SSI system when we were testing on the then-novel system on the DC Lines resignalling in 1988. It was the first application in an area with both AC and DC electrified lines and the longest data cables installed at the time. We set up monitoring equipment on the signalling power supply at Harrow & Wealdstone. Within a couple of hours of watching the scope trace I was able to predict the type of loco or MU approaching before it came into sight by the pattern of the  distortion on the 50hz wave form. A very simple bit of bolt-on filtering was enough to reduce the problem to an acceptable level.

Modern traction control systems can throw out lots of electrical garbage, to the extent that I believe one recent class required over a ton of onboard equipment to eliminate it.

 

The site work on Thameslink produced some very interesting data on stray DC traction retur n currents which behaved totally differently to our expectations in some areas. Before the DC was extended into Farringdon we took background measurements because of the proximity to LUL lines to give us a baseline. We then made a temporary connection of the rails between Farringdon and Blackfriars. As a worst case scenario in at the time we had the nearest SR substation disconnected and ran an 8-car train of Class 455 stock into Holborn Viaduct station, stopping at Blackfriars and acceleration over the hump in the track at something like 1 in 100 rising gradient with no other trains running on our side of the feeder station that was in use.

The split at Farringdon wasn't in the proportions expected, much more going towards Moorgate than we predicted. I set off with an ammeter to find what was flowing through the common rail that way. There was a big current flowing through the third structure bond. When I looked up I saw that the bond was connected to the steelwork holding up Smithfield Market, which I assume had somewhere a bond to an electricity Board earth.

In the other direction there was a significant reduction in Kings Cross Tunnel where the OHLE is bonded to the Fleet Sewer.

It was still possible to see the traction current signature of the test train at West Hampsted PSB and Silkstream Junction, but the big mystery was that the background level was being depressed. 

From revised calculations based on the results it appeared that there could actually be a null point in Belsize Tunnels where they crossed the Northern Line.

 

The least said about 'The Italian Job' the better. I'm sure the Wombat will understand.

[jim.snowdon]

7 hours ago, TheSignalEngineer said:

I'm not sure how much they dismiss it.

My reading of continental practice is that they understand it much better as not being the ogre that the British Utility companies would like to believe it to be, largely because they have been running street tramways on a nominally continuous basis. At the time the second generation tramways were starting to appear in Britain there was at least a complete generation gap in the experience of the Utility company engineers (not to mention a marked reluctance of certain of them to talk to their counterparts elsewhere in the country). There is a generally held view amongst those in Europe that 12" of largely mass concrete, which is typically what is under the track, is sufficient to stop a lot of stray current. So is putting down a plastic membrane before the concrete is poured.

8 hours ago, TheSignalEngineer said:

The site work on Thameslink produced some very interesting data on stray DC traction retur n currents which behaved totally differently to our expectations in some areas. Before the DC was extended into Farringdon we took background measurements because of the proximity to LUL lines to give us a baseline.

The behaviour of these overlap sections, where the track is Earthed at the AC end and floating ('earthy') at the DC end is quite interesting, not least as on occasions when running rails have been accidentally connected to Earth quite large currents can flow, despite the rail to earth potentials being very small. It still comes as a bit of a surprise that nothing has happened at Euston, where the DC lines have shared earthed tracks all the way up Camden for the last 50-odd years.

8 hours ago, TheSignalEngineer said:

When I looked up I saw that the bond was connected to the steelwork holding up Smithfield Market, which I assume had somewhere a bond to an electricity Board earth.

In the other direction there was a significant reduction in Kings Cross Tunnel where the OHLE is bonded to the Fleet Sewer.

That reminds me that when Seeboard (as they were at the time) were looking for any stray currents from Croydon Tramlink around the Addington area they ended up finding that the cable armouring virtually everywhere was awash with stray currents from all over the place. The conclusion was that it was largely a consequence of having a large interconnected cable network thoroughly overlaid by an equally large DC railway, aka Southern Region, which had, of course, been functioning (and leaking) for many decades.

 

[TheSignalEngineer]

8 hours ago, jim.snowdon said:

It still comes as a bit of a surprise that nothing has happened at Euston, where the DC lines have shared earthed tracks all the way up Camden for the last 50-odd years.

Prior to the AC electrification all track circuits on both the DC Lines and non-electrified lines were 50hz AC with vane relays. When the resignalling for AC electrification was done they were converted to 83 1/3hz operation. The DC Lines job between Primrose Hill and Watford Junction in 1988 used Reed track circuits of certain frequencies not affected by noise put out by BR and LUL stock. The trains used on the Bakerloo from Queens Park to Harrow and Wealdstone at the time could emit an exact Reed frequency used on some parts of BR at that time. The last resignalling saw WCML Track Circuits replaced by Axle Counters.

[Edwin_m]

10 hours ago, jim.snowdon said:

My reading of continental practice is that they understand it much better as not being the ogre that the British Utility companies would like to believe it to be, largely because they have been running street tramways on a nominally continuous basis. At the time the second generation tramways were starting to appear in Britain there was at least a complete generation gap in the experience of the Utility company engineers (not to mention a marked reluctance of certain of them to talk to their counterparts elsewhere in the country). There is a generally held view amongst those in Europe that 12" of largely mass concrete, which is typically what is under the track, is sufficient to stop a lot of stray current. So is putting down a plastic membrane before the concrete is poured.

The behaviour of these overlap sections, where the track is Earthed at the AC end and floating ('earthy') at the DC end is quite interesting, not least as on occasions when running rails have been accidentally connected to Earth quite large currents can flow, despite the rail to earth potentials being very small. It still comes as a bit of a surprise that nothing has happened at Euston, where the DC lines have shared earthed tracks all the way up Camden for the last 50-odd years.

That reminds me that when Seeboard (as they were at the time) were looking for any stray currents from Croydon Tramlink around the Addington area they ended up finding that the cable armouring virtually everywhere was awash with stray currents from all over the place. The conclusion was that it was largely a consequence of having a large interconnected cable network thoroughly overlaid by an equally large DC railway, aka Southern Region, which had, of course, been functioning (and leaking) for many decades.

 

It's partly because British utilities are privatised and therefore much more sensitive to anything that might cost them money.  

 

On the situation with Network Rail, I'm sure Jim will remember the shenanigans in Croydon trying to get the then Railtrack (also privatised) to accept the trams in proximity.  Much of the problem there was the use of 1970s-vintage 50Hz and audio frequency track circuits, which could give a false clear if an amp or so of AC at the wrong frequency and phase finds its way into the rails.  The trams have AC traction drives that range through these frequencies as the vehicle accelerates, and unlike the railway versions do not have software that jumps over sensitive frequencies.  The motor currents at these frequencies could be in the hundreds of amps, though the traction electronics will filter this so much less appears in the supply and return.  This is unlike older trams with traditional DC contactors, which would generate short spikes but not continuous harmonics of a particular frequency, and are electrically similar to but less severe than traditional Southern EMUs.  Although older traction is worse for interference in some ways (there are reports that the 4REPs could change signal aspects on the Bournemouth line), everyone had learned to live with them.  

 

More modern railway signalling has greater immunity, using track circuits that need to "see" a more complicated combination of frequencies before showing unoccupied, or axle counters where all circuitry is insulated from the rails.  However the signalling at New Street still goes back to the 1960s, though some equipment may have been replaced.  

[jim.snowdon]

2 hours ago, Edwin_m said:

It's partly because British utilities are privatised and therefore much more sensitive to anything that might cost them money.  

 

On the situation with Network Rail, I'm sure Jim will remember the shenanigans in Croydon trying to get the then Railtrack (also privatised) to accept the trams in proximity.  Much of the problem there was the use of 1970s-vintage 50Hz and audio frequency track circuits, which could give a false clear if an amp or so of AC at the wrong frequency and phase finds its way into the rails.  The trams have AC traction drives that range through these frequencies as the vehicle accelerates, and unlike the railway versions do not have software that jumps over sensitive frequencies.  The motor currents at these frequencies could be in the hundreds of amps, though the traction electronics will filter this so much less appears in the supply and return.  This is unlike older trams with traditional DC contactors, which would generate short spikes but not continuous harmonics of a particular frequency, and are electrically similar to but less severe than traditional Southern EMUs.  Although older traction is worse for interference in some ways (there are reports that the 4REPs could change signal aspects on the Bournemouth line), everyone had learned to live with them.  

 

More modern railway signalling has greater immunity, using track circuits that need to "see" a more complicated combination of frequencies before showing unoccupied, or axle counters where all circuitry is insulated from the rails.  However the signalling at New Street still goes back to the 1960s, though some equipment may have been replaced.  

Part of my job was chairing the Stray Current Working Party for Tramlink and the Utilities could be easily divided into -

- Gas, who talked to their counterparts around the country and were aware of how things were going with the other tramways

- Electricity, who were fairly laid back about it

- Fibre optic networks, who were so laid back they largely didn't bother. Their only real concern was us putting traction poles in the footpaths.

- BT, who were much like Gas, and remarkably pragmatic when we did find one instance of stray current taking a shortcut through the lead sheath of one of their cables.

- Water, who believed that they were unique and, you would think, somehow superior to their regional counterparts. They were humbled a bit when we pointed out to them that the stray current they had found in a major water main near Wimbledon was not ours but Southern Region's, especially as it was forming a neat parallel path back to Raynes Park substation.

 

As regards the signalling issues, I can well remember the fun there was with Railtrack over the Beckenham Line, where the tramway was ultimately accepted by demonstrating that even with all 24 trams on the section at once the interference levels were not sufficient to cause a problem. In a previous world, I can remember the concerns that LU's Signalling Engineer had over the Experimental Tube Train (the 1973 t/s unit fitted with the Westinghouse chopper traction equipment that later formed the basis for the DLR B90/92 stock), and the embarrassment when it was discovered that it was electrically quieter than the camshaft equipped 1973t/s that had by them taken over the Piccadilly Line. It was also well known that a C stock set with an earth fault on a traction motor would go through the track circuit frequency every time it started and stopped, but we all lived with that, much like the Metropolitan Line had lived with the stranger habits of the Metadyne equipped O and P stock, which would routinely 'bob' track circuits.

 

[melmerby]

4 hours ago, Edwin_m said:

 However the signalling at New Street still goes back to the 1960s, though some equipment may have been replaced.  

Some of the colour light signals are so rusty, they look like they might fall off their mountings. (probably not but they are very rusty)

[jim.snowdon]

5 hours ago, melmerby said:

Some of the colour light signals are so rusty, they look like they might fall off their mountings. (probably not but they are very rusty)

It couldn't be any more embarrassing than having signals fall across the tracks on account of the pole having rusted through at the base. 

 

[uax6]

On 18/09/2021 at 21:30, jim.snowdon said:

It couldn't be any more embarrassing than having signals fall across the tracks on account of the pole having rusted through at the base. 

 

 

Which, of course, has never happen ever.... Report 15/2015: Collision with a collapsed signal post at Newbury - GOV.UK (www.gov.uk)

 

Andy G

 

Grrr, I can't get the raib report to go as a hyperlink. 

Edited September 21, 2021 by uax6

[Edwin_m]

59 minutes ago, uax6 said:

 

Which, of course, has never happen ever.... Report 15/2015: Collision with a collapsed signal post at Newbury - GOV.UK (www.gov.uk)

 

Andy G

 

Grrr, I can't get the raib report to go as a hyperlink. 

Try https://www.gov.uk/raib-reports/collision-with-a-collapsed-signal-post-at-newbury.  On RMWeb you have to use the hyperlink button and paste it into the window that appears, you can't just paste into the text.  

 

I've an idea one fell over on the South Wales main line a few years before, but nothing hit it.  Perhaps Western Region signals were particularly vulnerable, despite few of them being near any sources of stray current?  

Edited September 21, 2021 by Edwin_m

[melmerby]

An update on the Hagley Road Extension, which is nearing completion.

(Taken last Thursday)

 

It seems I have misunderstood the powering of this section.

It would appear that it is still battery as far as the stop half way up Broad St (Brindley Place), then wired to Five Ways stop (not much sign of this stop so far), then battery again through the underpass, with the wires re-appearing just short of the terminus at 54 Hagley Road.

An awful load of pants up and down.

 

Starting from the present stop (Library/ICC):

 

 

By the Brasshouse:

(Notice still no OHLE)

 

Two views approaching the Brindley Place stop:

Notice the terminated wiring from Five Ways direction.

 

The stop itself almost complete:

 

 

 

Outside the Novotel the wiring gets rather complex:

The short stretch through the stop ends at tensioners with a second conductor taking over

 

 

Outside Moda Living tower block they building work has stopped the paving upgrade (so far):

 

 

At the entrance to the underpass the wires have gone again:

 

 

Because they have been terminated in these tensioners:

Another very short piece of conductor.

 

 

Meanwhile in Hagley Road you can see the wires start again after this scissors crossover approaching the terminus

I don't know what the chaps were doing but this concrete is a pale green colour!

 

Another view:

 

 

Finally the Terminus:

54 Hagley Road. I think it's grassedbecause they pinched the front lawn to lay tracks😄

 

 

Not much likelyhood of going any further in the near future☹️

 

 

Edited April 20, 2022 by melmerby

[melmerby]

An update on the track relaying in Birmingham City centre, including the triangular junction for the Eastside extension.

 

Stephenson Street, the extent of the relaying.

Towards the Town Hall etc.

 

Looking up Stephenson Place to New Street & Corporation Street:

 

Looking back from New Street:

 

Looking up Corporation Street from New Street:

 

Further up Corporation Street towards Bull Street and the junction:

 

The OHLE is cut back & grounded over the junction area:

 

Looking from near the Bull Street stop towards the junction:

 

Triangular Junction looking towards Lower Bull Street from Corporation Street (southern side):

 

 

Looking from Bull Street to Lower Bull Street:

 

A different angle Bull Street > Lower Bull Street:

 

 

Looking from Lower Bull Street towards Bull Street:

 

The two routes converging in Lower Bull Street:

But very unfinished

 

 

A couple more items to come

 

 

 

 

 

 

 

 

 

 

 

Edited April 20, 2022 by melmerby

[melmerby]

As part of the works there has been some incredible new valve arrangements in the water main system:

 

 

 

 

Just for completeness, Tram 20 having just arrived in Bull Street is about to return to Wolverhampton:

 

 

 

Edited April 11, 2022 by melmerby

[wagonbasher]

11 hours ago, melmerby said:

As part of the works there has been some incredible new valve arrangements in the water main system:

 

 

 

 

Just for completeness, Tram 20 having just arrived in Bull Street is about to return to Wolverhampton:

 

 

 

Those sleepers are completely different to the ones in Wolves…. The other end of the line is laid on sleepers that are two concrete ‘feet’ joined together with two lengths of steel angle, probably 50mm angle.  How odd.

 

Andy

[PhilJ W]

1 hour ago, wagonbasher said:

Those sleepers are completely different to the ones in Wolves…. The other end of the line is laid on sleepers that are two concrete ‘feet’ joined together with two lengths of steel angle, probably 50mm angle.  How odd.

 

Andy

Probably because of the pipework and future access to the pipework without ripping up the track.

[melmerby]

Unfortunately I haven't seen the earlier work on the relaying but bi-block sleepers have been used before.

[melmerby]

Looking back at previous tracklaying (all in this thread) the bi-block sleepers seem to be the standard away from certain more complex areas, as with these in Pinfold Street:

 

Also this from 2014 in Bull Street

Edited April 20, 2022 by melmerby

[melmerby]

https://metroalliance.co.uk/tram-travels-along-broad-street-for-first-time-as-testing-of-new-route-gets-underway/

[melmerby]

I was able to get into Brum last Thursday and see the finished West Side extension

The service has been running since just before the Commonwealth Games.

Due to the number of trams out of service undergoing rectification to body cracks, only 5 trams/hour sre currently running, consisting all the new trams plus a few of the first batch that have been repaired.

 

Some photos.

 

Broad Street from the end of the previous section. Hyatt to the left ICC to the right:

 

A little further along with Soloman Cutler to left and "Reflex" to right, Brasshouse stright ahead:

 

Alongside the "Reflex" with tram 34 on the way to Wolverhampton:

 

A little further along:

 

The start of the catenary which runs from the Broad Street stop to the Five Ways stop:

(The cyclist shouldn't be there, buses & trams only along this stretch!)

 

Between the Broad Street & Fiveways Tram Stops:

(Another illegal cyclist, none seem to obey the rules and nobody stops them)

 

Near the Five Ways tram stop, after which it is catenary free through the underpass until the terminus:

 

Five ways underpass, end of the catenary

(some limited stop bus services share the underpass with the trams, no other traffic allowed.)

 

A few more pictures follow, to complete coverage of this extension.

Edited August 25, 2022 by melmerby

[Siberian Snooper]

I bet the cyclists will be the 1st to try and make a claim against the council when they fall off, by getting a wheel caught in the track. I hope they get short shrift.

 

 

[Edwin_m]

3 hours ago, melmerby said:

 

 

That's absolutely asking for other vehicles to use the tramway.  I suspect 90% of drivers don't understand the blue "tram only" (tram and bus in this case) sign and most other tramways have moved to a no entry sign with "Except Trams" plate.  There's also no other indication of other traffic diverting except a dotted line and arrow that could easily be missed, especially if driving close behind a tram.  Fortunately this diveunder has a full road surface to accommodate the buses, so cars won't get trapped like they commonly do in Nottingham and Manchester despite those having various extra deterrents fitted.  

2 hours ago, Siberian Snooper said:

I bet the cyclists will be the 1st to try and make a claim against the council when they fall off, by getting a wheel caught in the track. I hope they get short shrift.

 

 

From safety discussions on Metrolink, there at least the approach is to provide cyclists with a reasonable signed alternative, but not worry too much if they don't choose to use it.  This provides a defence against those sorts of claims.  

Edited August 25, 2022 by Edwin_m

[Phil Parker]

2 hours ago, Siberian Snooper said:

I bet the cyclists will be the 1st to try and make a claim against the council when they fall off, by getting a wheel caught in the track. I hope they get short shrift.

 

 

 

Highway Code Rule 300: You should avoid driving directly on top of the rails and should take care where trams leave the main carriageway to enter the reserved route, to ensure you do not follow them.

 

Them's the rules.

[melmerby]

1 hour ago, Edwin_m said:

That's absolutely asking for other vehicles to use the tramway.  I suspect 90% of drivers don't understand the blue "tram only" (tram and bus in this case) sign

 

Ignorance is no excuse under the law.

 

1 hour ago, Edwin_m said:

most other tramways have moved to a no entry sign with "Except Trams" plate.

They already tried that and it was ignored as well:

The taxi will be taking someone to New Street station to drop them off in Stephenson Street, where they shouldn't even be. Fairly common.

I actually witnessed an illegal cyclist become a cropper on that bend trying to move across the road, front wheel duly stuck in the track and he went straight over the handlebars.

 

Whilst there is no enforcement, road users will ignore signs.

[coline33]

Clearly, there is something wrong with the signage and I am surprised that there is no official monitoring of the situation to determine necessary modification. 

[Mark Saunders]

58 minutes ago, Phil Parker said:

 

Highway Code Rule 300: You should avoid driving directly on top of the rails and should take care where trams leave the main carriageway to enter the reserved route, to ensure you do not follow them.

 

Them's the rules.

Remember the ending of Genevieve !

[melmerby]

30 minutes ago, coline33 said:

Clearly, there is something wrong with the signage and I am surprised that there is no official monitoring of the situation to determine necessary modification. 

What is wrong?

The signs comply with the law and highway code (which all road users should be familiar with)

If they can't understand them they shouldn't be driving/riding.

 

There have been complaints in Birmingham about the signage for the clean air zone (CAZ), with some motorists saying "I didn't see them so they are not obvious enough"

I have been along the exact pieces of road and I couldn't miss them. AFAIAC they are as obvious as they need to be, any more would be information overload.

They are also some complaining it's unfair on people driving older vehicles. Surely that's the whole point of it?