Woofferton Emergency Brake Application

[ReeceEmmitt]

Hello there – bit of a strange question – or perhaps not…

Yesterday I was on the delayed 1W98 1934 from Cardiff to Holyhead (158838). Just outside Woofferton there was a period of very sharp braking and we came to a stand. I must admit, considering the news of the last week I did give the table I was sat at a bit of a grip.

When we came to a halt, the guard announced on the tannoy that he was very sorry for the aggressive brake application, but ‘there is a large TV antenna nearby and it has interfered with the trains systems and commanded an emergency brake application. It’s not particularly common, but unfortunately has happened to us. Hopefully we will be under way again soon…’ No sooner as he said soon, we were off again and the rest of the journey passed without a hitch.

I take a passing interest in the railway but that’s about it, so no technical knowledge to speak of – I wonder if anyone could shed some light on what happened?

Thanks!

 

[185143]

Hello there – bit of a strange question – or perhaps not…

Yesterday I was on the delayed 1W98 1934 from Cardiff to Holyhead (158838). Just outside Woofferton there was a period of very sharp braking and we came to a stand. I must admit, considering the news of the last week I did give the table I was sat at a bit of a grip.

When we came to a halt, the guard announced on the tannoy that he was very sorry for the aggressive brake application, but ‘there is a large TV antenna nearby and it has interfered with the trains systems and commanded an emergency brake application. It’s not particularly common, but unfortunately has happened to us. Hopefully we will be under way again soon…’ No sooner as he said soon, we were off again and the rest of the journey passed without a hitch.

I take a passing interest in the railway but that’s about it, so no technical knowledge to speak of – I wonder if anyone could shed some light on what happened?

Thanks!

I've had this happen before.

I *think* a signal (from the Antenna I mean, not of a railway nature) interferes with the ERTMS equipment used on the Cambrian line and activates it. As it obviously won't pick up an ERTMS signal in that area, it commands an emergency brake application.

 

[Llanigraham]

The radio aerial say there ( not TV ) can cause interference with the ERTMS system of the Cambrian trains if it had not been shut down properly.

 

[JN114]

I don’t know, but from the guards announcement if you were on a 158 -

If the TV antenna is interfering with GSM-R, it can cause a “loss of secure comms to RBC (Radio Block Centre)”, which would, even when running on a non-ETCS line such as the Marches, result in a brake application until connection can be re-established.

Normally a few minutes for driver to reboot ETCS and on you go - at least that’s how it goes on our ETCS 387s on the Heathrow Express.

 

[MP393]

I have also had an emergency brake application in that area when travelling that line before too, and was on a 158 too!

 

[sd0733]

It's to do with the ERTMS on the 158s so you wont get it on any other traction.
1W76 is the usual one that gets stopped but strangely last night that one went straight through.
Tests have taken place but seemingly with no solution and given the limited expected life of 158s through Wooferton I cant see to many resources being put into the issue

 

[DerekC]

Interesting. According to public information the nearest transmitters are at Tenbury Wells and Ludlow but both are low power - in the region of 9-10 watts total effective radiated power, if I am understanding the information right. So interfering sufficiently with GSM-R to cause an EB sounds improbable. Am I missing something?

 

[davews]

Wooferton has various shortwave broadcasting transmitters and is the only remaining shortwave transmitter in the country, along with a couple of relatively low power local radio FM and medium wave transmitters. It is right next to the railway line.

Woofferton transmitting station - Wikipedia

en.wikipedia.org

The shortwave transmitters in use will vary according to time and day schedule. Note that yesterday there was a big geomagnetic storm from the sun which hit the earth, they may have had to adjust their schedule because of this.
So will probably only happen through Wooferton and totally unpredictable. It must have been a scary thing with the other things that happened this week.

 

[Ducatist4]

They have HF transmitters running at 500kw and the local FM transmitter is running at 1Kw - that's quite a lot of power in radio terms.

 

[Wyrleybart]

It's to do with the ERTMS on the 158s so you wont get it on any other traction.
1W76 is the usual one that gets stopped but strangely last night that one went straight through.
Tests have taken place but seemingly with no solution and given the limited expected life of 158s through Wooferton I cant see to many resources being put into the issue

Might not the replacement 197s have a similar reaction then ?

 

[185143]

It's to do with the ERTMS on the 158s so you wont get it on any other traction.
1W76 is the usual one that gets stopped but strangely last night that one went straight through.
Tests have taken place but seemingly with no solution and given the limited expected life of 158s through Wooferton I cant see to many resources being put into the issue

And it was 1W76 I got stopped on.

 

[sd0733]

Might not the replacement 197s have a similar reaction then ?

It's a possibility, but youd hope that the system fitted to 197s is more advanced and able to better cope with "foreign" signals. Time will tell on that one.

 

[Llanigraham]

Interesting. According to public information the nearest transmitters are at Tenbury Wells and Ludlow but both are low power - in the region of 9-10 watts total effective radiated power, if I am understanding the information right. So interfering sufficiently with GSM-R to cause an EB sounds improbable. Am I missing something?

You are, missing something that is. What you have looked at are TV transmitters, and the array at Woofferton has nothing to do with TV, but are radio transmitters, on numerous frequencies, from Ultra Low to quite high, and not just for the BBC World Service, as some seem to think. We were told that some transmissions were for the MOD.

At one stage it was quite common at Bromfield to get a phone call from Woofferton Box saying a particular train had stopped, often early in a night shift, say around 1900 and then sometimes later at around 2200. It did seem to reduce after drivers from the relevant depots were instructed to ensure that the ERTMS units were shut down properly.

Interestingly in never seemed to affect the DOWN trains, only the UP's (northbound)

 

[DerekC]

Wooferton has various shortwave broadcasting transmitters and is the only remaining shortwave transmitter in the country, along with a couple of relatively low power local radio FM and medium wave transmitters. It is right next to the railway line.

Woofferton transmitting station - Wikipedia

en.wikipedia.org

The shortwave transmitters in use will vary according to time and day schedule. Note that yesterday there was a big geomagnetic storm from the sun which hit the earth, they may have had to adjust their schedule because of this.
So will probably only happen through Wooferton and totally unpredictable. It must have been a scary thing with the other things that happened this week.

That's what I was missing - lots of transmitting power including 100s of kW of digital radio.

It's to do with the ERTMS on the 158s so you wont get it on any other traction.
1W76 is the usual one that gets stopped but strangely last night that one went straight through.
Tests have taken place but seemingly with no solution and given the limited expected life of 158s through Wooferton I cant see to many resources being put into the issue

It's a possibility, but youd hope that the system fitted to 197s is more advanced and able to better cope with "foreign" signals. Time will tell on that one.

I hope that somebody has investigated, found out what is causing the problem and demonstrated that it can't happen with other designs. It's odd, because the ERTMS is running in Level 0, in which it doesn't look for anything from GSM-R. Of course if you have unshielded wiring and a poor design not well proofed against interference sufficiently close to a high power transmitter you can get all sorts of strange things happening!

 

[1955LR]

When I worked for Rover we had the same issues on some early electronic engine management on vehicles when driving past the Long Wave transmitter at Droitwich. The engines would cut out, All resolved with with careful design of the ecu's and wiring . The 158's design should comply with various electromagnetic immunity standards , but it can take only a small change such as putting a cover back incorrectly or not clipping a wiring loom away properly to compromise the immunity.

 

[JN114]

It's odd, because the ERTMS is running in Level 0, in which it doesn't look for anything from GSM-R.

I’m not fully au-fait with the setup on the TfW 158s, but on our 387s, even if they’re running in NTC (Level 0), ETCS is still registered with GSM-R; and a loss of GSM-R in NTC will cause a brake demand for loss of secure comms.

I can’t see why the 158s would behave any differently, it’s meant to be a standard system.

 

[craigybagel]

Very common issue, it's been going on for years (probably since the 158s were fitted with ERTMS). It only happens at certain times of day - but annoyingly one of those times is in the evening when 1W76 passes through. Since the last timetable change the preceding train (1W98 1934 Cardiff - Holyhead) has also been booked for a 158 and is similarly afflicted. When 158s appear on other services they rarely have the same issue occur.

Tests were carried out a few months ago with a 158 spending a night shuttling back and forth between Craven Arms and Leominster to try and get to the bottom of it but no luck so far.

Hopefully the 197s will be fine - only some of the fleet is being fitted with ERTMS and those particular units are not likely to be passing Wooferton very often - and even if they do, it's likely that the ERTMS equipment will have come from a rather more reputable supplier than Ansaldo.....

== Doublepost prevention - post automatically merged: 5 Nov 2021 ==

That's what I was missing - lots of transmitting power including 100s of kW of digital radio.



I hope that somebody has investigated, found out what is causing the problem and demonstrated that it can't happen with other designs. It's odd, because the ERTMS is running in Level 0, in which it doesn't look for anything from GSM-R. Of course if you have unshielded wiring and a poor design not well proofed against interference sufficiently close to a high power transmitter you can get all sorts of strange things happening!

I don't believe it's anything to do with GSM-R, or at least the fault code that comes up on the screen makes no mention of it anyway.

I’m not fully au-fait with the setup on the TfW 158s, but on our 387s, even if they’re running in NTC (Level 0), ETCS is still registered with GSM-R; and a loss of GSM-R in NTC will cause a brake demand for loss of secure comms.

I can’t see why the 158s would behave any differently, it’s meant to be a standard system.

Do you get a brake demand for if you lose GSM-R signal (the "fart in the bathtub" warning). Those are pretty common on the TfW network (though I don't sign the level 2 routes so can't speak for that) and don't have any effect on the 158s.

When you set up ERTMS on the 158s when you set up the cab it registers the train on GSM-R if you have the right code - but if you don't have the code you can you type in any old number, and then still register on GSM-R in the normal way afterwards. Again, this doesn't appear to have any affect on brake demands, though again I've not tried this on level 2.

 

[tomuk]

Hopefully the 197s will be fine - only some of the fleet is being fitted with ERTMS and those particular units are not likely to be passing Wooferton very often - and even if they do, it's likely that the ERTMS equipment will have come from a rather more reputable supplier than Ansaldo.....

The reputable supplier in question is CAF itself.

 

[AlbertBeale]

Wooferton has various shortwave broadcasting transmitters and is the only remaining shortwave transmitter in the country, along with a couple of relatively low power local radio FM and medium wave transmitters. It is right next to the railway line.

Woofferton transmitting station - Wikipedia

en.wikipedia.org

The shortwave transmitters in use will vary according to time and day schedule. Note that yesterday there was a big geomagnetic storm from the sun which hit the earth, they may have had to adjust their schedule because of this.
So will probably only happen through Wooferton and totally unpredictable. It must have been a scary thing with the other things that happened this week.

It is indeed radio not TV at Woofferton. As said here, it's primarily a site (the UK site now) for BBC World Service short wave transmissions. Contrary to a comment above, I don't believe there are any digital radio transmissions from there, though there is a local commercial station on FM. (The geographical range of digital radio coverage - at least as far as BBC services are concerned - is less universal than FM, despite the number of local DAB relay transmitters catching up with the number of FM local relay transmitters now. But neither exists at Woofferton.) There used to be a medium wave service carrying the local BBC radio station at Woofferton, but that closed - BBC cost-cutting has meant a lot of local radio medium wave transmissions have stopped in recent years.

So could it be old-fashioned short-wave AM radio causing the problem with the railway communications (given that it's a powerful set of transmitters there)?

 

[1955LR]

I spoke yesterday to someone who recently worked at Woofferton and he said the rail system frequency and radio frequency transmissions from the site are very close together . From memory he said one being 3.995 MHz and the other 3.954 MHz . I would be easy for the one to overpower the other under certain circumstances such as poor filtering

 

[DerekC]

I spoke yesterday to someone who recently worked at Woofferton and he said the rail system frequency and radio frequency transmissions from the site are very close together . From memory he said one being 3.995 MHz and the other 3.954 MHz . I would be easy for the one to overpower the other under certain circumstances such as poor filtering

Wooferton seems to transmit in a large number of HF bands from 3.955 MHz to 17.830 MHz.

GSM-R channel frequencies are in the following bands:

• Uplink: 876–880 MHz
• Downlink: 921–925 MHz

However the ETCS balise frequencies are:

• Downlink (powers balise): 27.095 MHz
• Uplink (data back to train): 3.951 MHz for a logical '0' and 4.516 MHz for a logical '1'

So interference with the balise reader would seem to be a possibility.

 

[Llanigraham]

Interesting, and fits into similar problems they had a Aberystwyth when ERTMS was first introduced, however what it doesn't explain is why it only seemed to affect UP (northbound) trains, and not the Down's.

 

[tomuk]

Wooferton seems to transmit in a large number of HF bands from 3.955 MHz to 17.830 MHz.

GSM-R channel frequencies are in the following bands:

• Uplink: 876–880 MHz
• Downlink: 921–925 MHz

However the ETCS balise frequencies are:

• Downlink (powers balise): 27.095 MHz
• Uplink (data back to train): 3.951 MHz for a logical '0' and 4.516 MHz for a logical '1'

So interference with the balise reader would seem to be a possibility.

Would the erection of some special fencing alongside the railway help?

 

[craigybagel]

Would the erection of some special fencing alongside the railway help?

Maybe, but good luck getting anyone to pay for it.

At the moment, it's adding 2 or 3 minutes delay to a couple of services a day - and even those aren't affected every time. It's a nuisance yes - but it's also not likely to be an issue in a few years time.

 

[D6130]

At the moment, it's adding 2 or 3 minutes delay to a couple of services a day - and even those aren't affected every time. It's a nuisance yes - but it's also not likely to be an issue in a few years time.

Doesn't it also run the risk of putting expensive wheelflats on the units concerned....especially at this time of year?

 

[hexagon789]

Doesn't it also run the risk of putting expensive wheelflats on the units concerned....especially at this time of year?

If the WSP is up to snuff it shouldn't.

 

[D6130]

If the WSP is up to snuff it shouldn't.

True....but I know from bitter experience of driving 158s that the WSP isn't always up to snuff! (or wasn't when I retired 9 years ago).

 

[hexagon789]

True....but I know from bitter experience of driving 158s that the WSP isn't always up to snuff! (or wasn't when I retired 9 years ago).

Perhaps the 158 system is a bit dated by modern standards, but I've been very impressed by modern kit.

Having seen the WSP in a 68 in action it is very impressive what can be accomplished.

 

[craigybagel]

Doesn't it also run the risk of putting expensive wheelflats on the units concerned....especially at this time of year?

I've never known any major issues from it even at this time of year - the WSP does tend to kick in but it deals with it pretty well in my experience.

I suspect if it really was a major issue TfW would avoid diagramming 158s to the problem trains - as I mentioned above, during the rest of the day 158s normally pass through with no issues whatsoever.

 

[tomuk]

Having a Google it appears that Woofferton only broadcasts on 3.995 MHz, in the ECTS balise band, at certain hours of the day

0500-0600 BBC World Service [English]
2000-2100 KBS (Korea) World Radio [German]
2100-2200 KBS (Korea) World Radio [German]