Driving Trains in foggy weather

[Jobi-wan]

I was out a couple of nights ago in fog so thick I couldn't see the rails along which I was travelling. Heightened senses and route knowledge are key. I drove normally most of the time but lost SA a couple of times so threw the brake on until I regained an indication of my exact location. It was only about 1 1/2 hours but my brain was working overtime and needed another hour or so (passing back) to calm back down to normal. Short answer is challenging but fun especially in the dark.

Couple of years ago I was hossing along at 75mph, could probably see about 10ft of rail in front of me. 4am on a class 4 train, about 1500 tons, going along on greens when all of a sudden this red haze started to appear through the thick fog. I reckon i was probably 200 meters from the signal when I saw it had gone back on me. Stupid signal fault. I was alright to continue by the time I'd changed my pants haha

 

[LNW-GW Joint]

It's a long time (1961-ish) since BR put a driver in front of the media to explain how his train (the Glasgow-Euston Caledonian) could maintain full speed (then 90mph behind a class 40) in thick fog, thanks to AWS (audible warning of signal aspects in the cab).
It actually took BR a long time to equip all main lines with AWS, and there were two incompatible standards - the modern BR and the older but obsolete GWR pattern.
Today's ETCS and equivalent cab signalling systems means signal aspects are delivered directly to train cabs, for speeds up to 320km/h, continually, fog or not.

 

[hexagon789]

It actually took BR a long time to equip all main lines with AWS

The Southern Region did without entirely until about 1978, when the London Bridge re-signalling which had AWS provision included, was completed. Rollout on mainlines started from about 1982 IIRC.

It's always interesting looking at old Sectional Appendices to see what was and wasn't AWS fitted, even as late as 1979 much of Scotland outside the Central Belt was unfitted.

The central part of the East-West TransPennine route (Man Vic to Leeds) seems to have lasted without AWS until around the time of Sprinterisation when some parts also gained higher permitted speeds for Multiple Units (somewhere around early 90s)

Inverness to Aberdeen was only equipped as late as 2000.

I believe some freight only lines may still be unfitted even now?

 

[InkyScrolls]

The Southern Region did without entirely until about 1978, when the London Bridge re-signalling which had AWS provision included, was completed. Rollout on mainlines started from about 1982 IIRC.

It's always interesting looking at old Sectional Appendices to see what was and wasn't AWS fitted, even as late as 1979 much of Scotland outside the Central Belt was unfitted.

The central part of the East-West TransPennine route (Man Vic to Leeds) seems to have lasted without AWS until around the time of Sprinterisation when some parts also gained higher permitted speeds for Multiple Units (somewhere around early 90s)

Inverness to Aberdeen was only equipped as late as 2000.

I believe some freight only lines may still be unfitted even now?

Even some passenger loops do not have AWS, for example Kirkstall Loops near Leeds.

 

[Signal Head]

How does TPWS give a driver an indication of the aspect of the signal they are approaching, or indeed the aspect of the previous signal? (assuming of course they are not 'overspeeding' towards a red)

It doesn't. TPWS is 'invisible' until an intervention occurs either due to overspeed or passing a Red.

 

[Islineclear3_1]

Fog marking points,generally about 200 yds from the box. It was either a signal,structure or marker that when it could not be seen during fog then it was officially foggy and Fogmen were called out to repeat the distant signals to the drivers. If the distant was “on” a detonator was placed on the rail and the driver shown a yellow handsignal. If “off” the the detonator was removed and the driver shown a green handsignal.
I’m not aware of anywhere in this country where “shooting the distants “ is still carried out. It’s certainly not in the rule book anymore.

Do you mean that in olden times, a fogman would actually walk along the line to the distant signal?. How fascinating.

 

[cool110]

Do you mean that in olden times, a fogman would actually walk along the line to the distant signal?

Some areas had multi-shot detonator placers that would just need periodic reloading, but elsewhere someone had to go out there to either place and remove them by hand or reload the single-shot placers after every use.

 

[ChiefPlanner]

Some areas had multi-shot detonator placers that would just need periodic reloading, but elsewhere someone had to go out there to either place and remove them by hand or reload the single-shot placers after every use.

A rotton and a dangerous job - there would be lists of nominated fogmen for particular distant signals held in signal boxes and Station Managers /Supervisors would have to find resources to get these people called out for duty. Often local PW staff. (read Gerry Fiennes work on the collision at Gidea Park in 1947 for a detailed example of how it worked out in practice)

Other things to assist drivers in those far off days were lit flares at stopping marks on stations to help drivers / motormen.

The stress on operating staff must have been immense working in those conditions - even with a "fog service" which was often 50% of the booked service.

 

[Ashley Hill]

The stress on operating staff must have been immense working in those conditions - even with a "fog service" which was often 50% of the booked service.

Plenty of welcome overtime pay for the local PW lads who performed the fogging duties though!

 

[12LDA28C]

It doesn't. TPWS is 'invisible' until an intervention occurs either due to overspeed or passing a Red.

I know, which is why I asked the question. AWS is rather more helpful in fog.

 

[craigybagel]

It doesn't. TPWS is 'invisible' until an intervention occurs either due to overspeed or passing a Red.

I know, which is why I asked the question. AWS is rather more helpful in fog.

Playing devil's advocate here - if you see a TPWS grid in the 4 foot appearing out of the gloom, your route knowledge should be able to tell you if there's a signal shortly afterwards. It can be a useful tool, amongst others.

 

[12LDA28C]

I believe some freight only lines may still be unfitted even now?

Not all passenger main lines are fitted with AWS either.

== Doublepost prevention - post automatically merged: 31 Dec 2024 ==

Playing devil's advocate here - if you see a TPWS grid in the 4 foot appearing out of the gloom, your route knowledge should be able to tell you if there's a signal shortly afterwards. It can be a useful tool, amongst others.

Indeed but of course an AWS magnet will tell you if the signal ahead is clear or not if you can’t see it, a TPWS grid won’t.

 

[TPO]

Is there any difference in Absolute Block signalling areas with semaphores for drivers or do they proceed as with other areas? I am of the impression that signallers of such places are required to report if specific siting points are not visible due to fog? So does this have implications for drivers?

Fog marking points,generally about 200 yds from the box. It was either a signal,structure or marker that when it could not be seen during fog then it was officially foggy and Fogmen were called out to repeat the distant signals to the drivers. If the distant was “on” a detonator was placed on the rail and the driver shown a yellow handsignal. If “off” the the detonator was removed and the driver shown a green handsignal.
I’m not aware of anywhere in this country where “shooting the distants “ is still carried out. It’s certainly not in the rule book anymore.

In modern AB 'boxes, if the Signaller cannot see the [tail lamp passing the] Clearing Point then they cannot give "train out of section" to the 'box in rear. So if it's that foggy there needs to be a means of relaying the information that the train has passed the Clearing Point with tail lamp on [i.e. confirming train is complete] and lit- or not.

Might have a Tail Lamp Camera available in some places, otherwise would need to get someone out on the ground to be the Signallers eyes on.

TPO

 

[Meerkat]

How does it work for foot crossings that don't have whistle boards - are the drivers expected to know where they are and use the horn?
Do you need to change the lights? I remember driving through thick fog and needing low beam to see the road, but high beam to see the trees in the distance to get some warning of which way the next corner went.
Does it ever get foggy enough for DOO problems - I guess it would only be ones based on mirrors?

 

[driverd]

The comment was made earlier about AOCL/ABCL. Would a line with a higher number of foot crossings/farm crossings also make you go "I'm going to ease off a bit, since I can't see the crossing as clearly" or stick with the usual "I'm approaching, I'm sounding my horn for the 3.0 seconds at the board, that's all that's needed"?

Absolute aside but there isn't a rule anywhere about 3.0 seconds. It's a certain TOC (or perhaps even depots) made up rules. It's common around the industry where a certain driver manager has an "idea" and it gets taken as gospel, despite being based on nothing sensible.

As far as crossings go, for me, I just use the horn additionally on approach to well known busy crossings. There's no requirement to slow down during fog/rain etc at foot crossings - arguably fog is just going to make the user a tad more cautious, as opposed to heavy rain, where the user is more likely to be in a hurry to cross and potentially have obscured vision and hearing due to a hood.

I understand that driving to signals rather than line of sight, and route knowledge, means you don't rely on what you can see to determine your driving, but are there bits which are made more difficult? Any more tension from the environment?

Semaphore signalling, without a doubt. In thick fog it can be a nightmare to spot your signal and we've all had the scare of mis-locating a signal at some point or another. I personally creep through the station limits if the distant was on (on my patch we've known fog so thick you can see the post but not the signal head - and that's since circa 2015).

 

[skyhigh]

Do you need to change the lights? I remember driving through thick fog and needing low beam to see the road, but high beam to see the trees in the distance to get some warning of which way the next corner went.

Trains don't have high/low beam, just day or night headlights.

The main purpose of headlights is for others to see the train anyway, so you wouldn't want to dim the lights when visibility was poor.

How does it work for foot crossings that don't have whistle boards - are the drivers expected to know where they are

Yes

and use the horn?

No

 

[12LDA28C]

How does it work for foot crossings that don't have whistle boards - are the drivers expected to know where they are and use the horn?
Do you need to change the lights? I remember driving through thick fog and needing low beam to see the road, but high beam to see the trees in the distance to get some warning of which way the next corner went.
Does it ever get foggy enough for DOO problems - I guess it would only be ones based on mirrors?

Train lights are not like car headlights - there is no low/high beam or fog lights. Headlights are only there to aid visibility of an oncoming train to anyone on or near the line, not to give drivers better view of the line ahead.

If a DOO driver cannot see the full length of their train for any reason, including due to thick fog, they would need to carry out a degraded dispatch by stepping out onto the platform and moving to a position that they could see the full length of their train before completing station duties.

 

[norbitonflyer]

It doesn't. TPWS is 'invisible' until an intervention occurs either due to overspeed or passing a Red.

My comment above now edited. TPWS would stop you if you missed a red, but AWS remains the main non-visual cue. (ETCS and ATP will also help in fog)

 

[43066]

TPWS would stop you if you missed a red

Not necessarily, as it isn’t fitted everywhere. It also doesn’t give you any indications unless you’ve already tripped it, or where the system is defective/isolated.


== Doublepost prevention - post automatically merged: 31 Dec 2024 ==

Absolute aside but there isn't a rule anywhere about 3.0 seconds. It's a certain TOC (or perhaps even depots) made up rules.

IIRC it’s part of the professional driving policy at GA (@dk1 could confirm).

 

[dk1]

Not necessarily, as it isn’t fitted everywhere. It also doesn’t give you any indications unless you’ve already tripped it, or where the system is defective/isolated.


== Doublepost prevention - post automatically merged: 31 Dec 2024 ==



IIRC it’s part of the professional driving policy at GA (@dk1 could confirm).

Yes at my TOC we have to give at least 3secs on the low tone 1 second before/2 seconds after a whistle board. It’s monitored and commented on on every download. I know many other operators are nowhere near as anal.

 

[43066]

Yes at my TOC we have to give at least 3secs on the low tone 1 second before/2 seconds after a whistle board. It’s monitored and commented on on every download. I know many other operators are nowhere near as anal.

Thanks. It does seem OTT. I know ASLEF recommend using two tones at whistle boards, which is also in excess of what the rule book requires.

 

[12LDA28C]

My comment above now edited. TPWS would stop you if you missed a red, but AWS remains the main non-visual cue. (ETCS and ATP will also help in fog)

AWS also gives a visual clue (the 'sunflower') of whether the previous signal was green or a cautionary aspect, in most circumstances.

 

[philthetube]

Could be challenging at full speed on LU with green to red signals and only a fog repeater placed 400’ (121m) in advance of the red, less than a trains length!

I googled this and it appears correct although it is certainly more than this on the MET, possibly correct on tube lines though, as they have lower speed limits.

I would have said that 400 yards was more accurate though they seem variable.

I am pretty sure Chiltern drivers would not be prepared to run at 60mph with repeaters that close.

 

[12LDA28C]

I googled this and it appears correct although it is certainly more than this on the MET, possibly correct on tube lines though, as they have lower speed limits.

I would have said that 400 yards was more accurate though they seem variable.

I am pretty sure Chiltern drivers would not be prepared to run at 60mph with repeaters that close.

Fog repeaters on the Met are indeed located as @Dstock7080 stated, 121m on the approach to the signal to which they relate.

 

[Surreytraveller]

My comment above now edited. TPWS would stop you if you missed a red, but AWS remains the main non-visual cue. (ETCS and ATP will also help in fog)

TPWS is only fitted at high risk signals. It will only stop you if you missed a red that has TPWS fitted.

 

[Meerkat]

Trains don't have high/low beam, just day or night headlights.

The main purpose of headlights is for others to see the train anyway, so you wouldn't want to dim the lights when visibility was poor.

I was thinking in terms of how when driving a car in thick fog high beam lights up a wall of white right in front of you and its harder to see anything else

No

If the horn is required for crossing with limited visibility distance then why isnt it needed for all foot crossings in fog - are the lights considered to have a sufficient 'range'?

 

[Egg Centric]

Train lights are not like car headlights - there is no low/high beam or fog lights.

Any idea what dimmed/full lights are used for on the stock that has them e.g. IETs? I had assumed they were to be used depending on the prevailiing visibility but that's only cause that's what I do in train sim world which is a bit of a circular argument

 

[LNW-GW Joint]

Even some passenger loops do not have AWS, for example Kirkstall Loops near Leeds.

The Chester station area is also without AWS today.

 

[TreacleMiller]

Any idea what dimmed/full lights are used for on the stock that has them e.g. IETs? I had assumed they were to be used depending on the prevailiing visibility but that's only cause that's what I do in train sim world which is a bit of a circular argument

Dimmed - Night time

Full - Daytime.

The lights are there so the train is visible to those who need to see it - not for us to see out the cab.

Full in heavy fog would be pretty dumb though - you cant see a thing!

 

[Egg Centric]

Dimmed - Night time

Full - Daytime.

The lights are there so the train is visible to those who need to see it - not for us to see out the cab.

Full in heavy fog would be pretty dumb though - you cant see a thing!

So is idea to not dazzle oncomers at night presumably?

I'm a sad Centric I've been doing totally the opposite thing to the right .