What is this track cabling and yellow box? (Photo)

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Lewis5949

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20210116_081024.jpg

I've seen this box and similar around the railway but I don't know what it is, and I don't know anyone personally to ask. The photo is from Reading Platform 6.

My guess is an axle counter or maybe something related to track circuit blocks. I know just beyond the basics of what those do but not the technical side including what lineside equipment looks like for both.

Thanks
 
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Magicake

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You are quite correct it is an axle counter. The yellow box is sometimes called a 'mushroom' informally.
 

Lewis5949

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You are quite correct it is an axle counter. The yellow box is sometimes called a 'mushroom' informally.
Thanks. How exactly do these work though? I would have expected a physical switch, weight plate - some sort of physical sensor, laser, etc.

Instead this looks like a version of some LU lines TBTC cables (that normally run alongside the track), or even like ASDO in how the beacon would transmit wirelessly.

I don't think train axles have any sort of communication equipment, so how does this work? Can the cable sense a change of magnetic field or something?
 

swt_passenger

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The sensors work on the wheel disturbing an electromagnetic field. No moving parts at all (except the wheels!)
 

Magicake

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When first installed they were set off accidentally a few times by p-way waving a shovel near them...
 

ac6000cw

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The sensors work on the wheel disturbing an electromagnetic field. No moving parts at all (except the wheels!)
I think if you follow the cables from the yellow box to the far rail - bottom of the photo - then zoom in, you can see things on either side of the rail which (I assume) are the wheel sensors.

As others have said, they use 'inductive' sensing - I guess the yellow box contains some of the processing/detection electronics.
 
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Lewis5949

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Hmm interesting, my guess about the electromagetic field looks correct, but equally the mention of the items on the outside of the rails looks true too - on the platform cess side I see two circular white things

View attachment 95458
The actual axle counter is not the cables but the rail mounted device outlined above. The cables just connect back to the yellow "mushroom".
So is it those white things measuring the electromagnetic field that sends the data back to the box? It surprises me how many cables are needed to do this and how they are wrapped around the chairs/pots
 

swt_passenger

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Hmm interesting, my guess about the electromagetic field looks correct, but equally the mention of the items on the outside of the rails looks true too - on the platform cess side I see two circular white things


So is it those white things measuring the electromagnetic field that sends the data back to the box? It surprises me how many cables are needed to do this and how they are wrapped around the chairs/pots
I expect four standard length factory assembled cables will be more reliable and consistent for setting up. Anything different about the cables or any locally made connections would probably lead to site specific tuning or whatever…
 

alxndr

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Hmm interesting, my guess about the electromagetic field looks correct, but equally the mention of the items on the outside of the rails looks true too - on the platform cess side I see two circular white things
The rail contacts on the inside of the rail and the outside of the rail are equally important. One is a pair of transmitters and one is a pair of receivers.
The yellow box (EAK - electronic junction box) transmits and receives to the rail contacts. It transmits this information back to a computer.
The computers take the information from multiple axle counters and uses this information to determine whether there is a train in the section or not.

So is it those white things measuring the electromagnetic field that sends the data back to the box? It surprises me how many cables are needed to do this and how they are wrapped around the chairs/pots
There will be two cables to each side of the rail. The two halves aren't directly connected together, just bolted to either side of the rail.
In the slightly newer version there are only two cables, but they perform exactly the same purpose, they've just put two cables within the same sheathing.
 

Annetts key

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They make great targets for Tamper clamps.:lol:
The older type, as shown in the photo in the posts above, are also not too happy if a rail grinding machine has its grinding wheels set too low...

In terms of advantages/disadvantages of track circuits vs. axle counters, don’t believe the sales pitch from the axle counter manufacturers. As they are just a tad bit biased...

If the electronics in the EAK get wet, that’s it, it will fail and will need to be replaced. So if the floodwater is deep enough, or the cover is not fully closed and it’s hammering down with rain or snow...

And because the evaluator is often far from the actual count heads / detection points, the techs when trying to fix a fault, may spend just as much time travelling back and forth as they do working on the equipment. Especially if it is found to be a cable fault.

And a single power supply fault to an evaluator rack, or an evaluator rack processor card fault can knock out twenty or more axle counter sections all at once.
 
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nlogax

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Those mushrooms seem to be absolutely everywhere on the WCML. Is freight the main reason for axle counter proliferation?
 

edwin_m

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Those mushrooms seem to be absolutely everywhere on the WCML. Is freight the main reason for axle counter proliferation?
I think they're seen (rightly or wrongly) as more reliable than track circuits, and not prone to electromagnetic interference. Another advantage, though not really applicable to the WCML, is that a long section only needs a counter head at each end but would need a separate track circuit every 500 metres or so, to be combined into one "logical" track circuit for the interlocking.

One problem with them is that if a train stops with a wheel right on one, it can confuse the counter and leave both sections showing occupied. So for example the Nottingham area was re-signalled with axle counters everywhere except in the platforms.
 

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Those mushrooms seem to be absolutely everywhere on the WCML. Is freight the main reason for axle counter proliferation?
No, track circuits have fallen out of fashion with Network Rail. Axle counters do have advantages, especially where there is OHL. Or where the existing signalling system is being replaced with a new signalling system.
 

TSG

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Those mushrooms seem to be absolutely everywhere on the WCML. Is freight the main reason for axle counter proliferation?
No. They're generally preferred because they:
  1. simplify electric traction return through the rails/bonding
  2. remove insulated joints from the rails improving integrity and reducing maintenance
  3. arguably have better immunity to traction emissions than track circuits
  4. modern versions can do some clever tricks like act as virtual track circuit interrupters, or replace multiple treadles reducing the equipment needed and thus costs
  5. modern versions also have some other tricks like double-block working round a failed head, that arguably put their availability ahead of track circuits
  6. obviously better tolerance to rail head conditions like rust or leaf fall than track circuits
  7. arguably they play better than track circuits if you want to centralise equipment in fewer but more accessible location case suites because long tail cables are less of a problem for axle counter
I first worked with axle counters 20 years ago or more and they were a pain in the arse then. Modern ones are much better and so are the procedures and standards around their use.
And a single power supply fault to an evaluator rack, or an evaluator rack processor card fault can knock out twenty or more axle counter sections all at once.
I think you make some good points and track circuits can do just as good a job in many situations, but I believe stuff like Frauscher can have redundant power supplies/evaluators/network connections etc now so they've improved
 

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I think they're seen (rightly or wrongly) as more reliable than track circuits, and not prone to electromagnetic interference.
Track circuit reliability exceeds 99.9999%. The main problem with them is the condition of the track, either the ballast being contaminated if on wooden sleepers, or worn insulators if the sleepers are concrete or steel. This can and does result in repeat failures especially during wet weather conditions.

At the moment, axle counter reliability is a bit flaky in my area, even though it’s all relatively new equipment.

I can’t comment about Frauscher types, as the type in my area is made by Thales.
 
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nlogax

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Thanks all, interesting to know. Really does sound like it's horses for courses when it comes to where they're used.
 

snowball

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I imagine if the power goes down and comes back, axle counters are more of a pain than track circuits, you have to start afresh working out where the trains are.
 

TSG

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I imagine if the power goes down and comes back, axle counters are more of a pain than track circuits, you have to start afresh working out where the trains are.
That’s true. However, off the top of my head I’d say the power requirements for axle counters would be rather lower than a track circuit equivalent scheme. As mentioned above it can be easier to concentrate axle counter equipment too. These factors can make it more cost effective to provide local UPS backup and reconfigurable power cable routing, improving security of supply. That mitigates the risk of ‘blind’ axle counters somewhat.
 

alxndr

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And because the evaluator is often far from the actual count heads / detection points, the techs when trying to fix a fault, may spend just as much time travelling back and forth as they do working on the equipment. Especially if it is found to be a cable fault.
Equally you could argue similarly for multiple section track circuits. They can be an absolute nightmare trying to race around all the relay ends to identify which section is at fault, and sod's law will say that either it's the opposite end to where you started or it rights itself before you manage to get to all of them. One blessing about axle counters is that even if they get restored they still give you information on the nature of the problem on the download.

Either track circuits nor axle counters are perfect. On irritating track circuit faults I've heard people say "I wish we could just rip it out and stick an axle counter in" and on axle counter faults I've heard the opposite. Axle counters aren't the demon I thought they were when they were first introduced here though.
 

swt_passenger

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Equally you could argue similarly for multiple section track circuits. They can be an absolute nightmare trying to race around all the relay ends to identify which section is at fault, and sod's law will say that either it's the opposite end to where you started or it rights itself before you manage to get to all of them. One blessing about axle counters is that even if they get restored they still give you information on the nature of the problem on the download.

Either track circuits nor axle counters are perfect. On irritating track circuit faults I've heard people say "I wish we could just rip it out and stick an axle counter in" and on axle counter faults I've heard the opposite. Axle counters aren't the demon I thought they were when they were first introduced here though.
Didn’t they get a bad reputation after a failure/incident in the Severn Tunnel? Maybe they just weren’t rugged enough for that purpose, at the time, and that view clouded everyone’s opinions for quite a time afterwards?
 

Nicholas Lewis

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One downside of axle counters is you don't get a warning on a broken rail that track circuited systems give so need more frequent ultrasonic testing to detect potential failures. However, more than offsets the reliability that axle counters bring and in DC areas its massively simplifies traction return cabling and removal of impedance bonds all potential sources of failure.
 

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I imagine if the power goes down and comes back, axle counters are more of a pain than track circuits, you have to start afresh working out where the trains are.
The type of axle counter equipment on my area has battery backup. But the battery capacity will only supply the systems for about between 30 and 60 minutes. That’s normally more than enough time for the 650V generator set to come on line. But of no use if a fuse, MCB or other power fault occurs down stream of the generator, as there is no way that staff can get to site before the batteries run out of energy.

And, yes, when a group of axle counters does fail, it causes operations big, big headaches for operations, especially if it’s a junction area and therefore locks the points on / at the junction.
That’s true. However, off the top of my head I’d say the power requirements for axle counters would be rather lower than a track circuit equivalent scheme. As mentioned above it can be easier to concentrate axle counter equipment too. These factors can make it more cost effective to provide local UPS backup and reconfigurable power cable routing, improving security of supply. That mitigates the risk of ‘blind’ axle counters somewhat.
That very much depends on which track circuit type you are comparing and to which type of axle counter system. Remember, low voltage DC track circuits can operate for months from a primary (non-rechargeable) cell. And the axle counter evaluators that are on my area are in REB equipment buildings, which require air conditioning units (some need two of these) to keep the temperature in the room cool. When the air conditioning fails, on a hot summer day, it increases the risk of the axle counter evaluators failing.

It is possible for track circuits to have battery backup. But it’s not normally considered to be necessary because a normal track circuit will recover seconds after the power is restored.
Equally you could argue similarly for multiple section track circuits. They can be an absolute nightmare trying to race around all the relay ends to identify which section is at fault, and sod's law will say that either it's the opposite end to where you started or it rights itself before you manage to get to all of them. One blessing about axle counters is that even if they get restored they still give you information on the nature of the problem on the download.

Either track circuits nor axle counters are perfect. On irritating track circuit faults I've heard people say "I wish we could just rip it out and stick an axle counter in" and on axle counter faults I've heard the opposite. Axle counters aren't the demon I thought they were when they were first introduced here though.
Multi-section track circuits do cause problems. But in my experience, this was only an infrequent problem, and mostly only affected track circuits on plain line in the countryside or similar long stretches. On, or near junctions, most track circuits were single sections, or two or three fairly short sections, where you could walk from end to end in less than ten minutes (if that).

But with the axle counter installations, some that cover junctions are miles and miles away from the REB with the evaluator. Of course, a lot of this is down to how good or bad the scheme design is.

There is no doubt that axle counters have a lot of advantages. Long sections, no problem with traction return conductor rails / return current on OHL areas. Not affected by rusty rails. No butt to butt IRJ failures in summer. Plus many others. But they also have various disadvantages that appear to be overlooked at times.
Didn’t they get a bad reputation after a failure/incident in the Severn Tunnel? Maybe they just weren’t rugged enough for that purpose, at the time, and that view clouded everyone’s opinions for quite a time afterwards?
That was not really the fault of the axle counters, but more railway poor procedures and poor design of the interface to the rest of the signalling system. That axle counter system did not have isolation links. And at the time, the remote control system (TDM system) was failed, so the signaller could not see on their panel the state of the real railway. It’s still unclear on what exactly happened, but somehow the axle counter section went clear while a train was in section. And because the protecting signal had not been restricted to red, once the axle counter section went clear, the through-routes/emergency override system in use, caused the protecting signal to automatically clear to a proceed aspect...

Now axle counters are provided with disconnection links, so that they can be worked on with no risk of a similar problem occurring (assuming that procedures are followed).

I’m not pro or anti axle counters or pro or anti track circuits. But I do hate stupid designs and less than practical scheme designs.
 

edwin_m

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One downside of axle counters is you don't get a warning on a broken rail that track circuited systems give so need more frequent ultrasonic testing to detect potential failures. However, more than offsets the reliability that axle counters bring and in DC areas its massively simplifies traction return cabling and removal of impedance bonds all potential sources of failure.
Another downside is that traincrew can't use track circuit clips to protect the adjacent line in the even of an accident such as derailing foul of it. The Stoke re-signalling, one of the first to use axle counters widely, had phones every few hundred metres in the cess as an alternative means of stopping trains in emergency. But I guess the advent of universal GSM-R with the emergency stop button is now considered enough to make that unnecessary, as it should stop other trains far more quickly than getting down to the track and applying a clip.

I recall reading the Newark flat crossing uses axle counters, possibly only on the east-west leg. I guess this is because of the difficulty of putting insulated joints in the four-foot of the crossings.
 

Bald Rick

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One downside of axle counters is you don't get a warning on a broken rail that track circuited systems give so need more frequent ultrasonic testing to detect potential failures. However, more than offsets the reliability that axle counters bring and in DC areas its massively simplifies traction return cabling and removal of impedance bonds all potential sources of failure.

Although, in track circuited areas only something like 20% of broken rails are picked up by track circuits. As you know, not all broken rails are a full clean break with an air gap, and not all track circuits cover both rails.


Another downside is that traincrew can't use track circuit clips to protect the adjacent line in the even of an accident such as derailing foul of it. The Stoke re-signalling, one of the first to use axle counters widely, had phones every few hundred metres in the cess as an alternative means of stopping trains in emergency. But I guess the advent of universal GSM-R with the emergency stop button is now considered enough to make that unnecessary, as it should stop other trains far more quickly than getting down to the track and applying a clip.

This came up first on the Euston job two years earlier, with the installation of axle counters through Primrose Hill Tunnel and a little way towards Kensal Green.

I’m wondering, though, when the last time a track circuit clip was used in an accident.
 

Tim M

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Although this is an advert it does illustrate how the Frauscher wheel sensor and axle counter system works. It has a number of advantages over other systems including ease of installation (and temporary removal while tamping is going on), no electronics trackside, simpler serial interface to some types of computer based interlockings (using the WESTRACE protocol), doesn’t count spokes on some types of wheels (Steam loco’s!), and significantly cheaper, etc. etc.. Frauscher is an Austrian Company.
 

Class 08

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Similar thing from Thales (France). Interestingly, they sometimes link axle counters to asset management systems (not just the interlocking), so you can still “see” the trains even if the interlocking fails.
 

aleggatta

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Isn’t there a country that has to have an operational restriction of no more than (something like) 256 axles per train due to design limitations of the axle counter system? (Vague recollection from a Matt Parker live show)
 
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