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Effect of fog on railways?

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Howardh

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Been reading the on-line papers and noted many flights cancelled + slow driving on motorways due to heavy fog.

No reports of any train delays or cancellations, so made me wonder has there been any fog-related train disruption today, and more widely how thick has fog to be to be a problem for the railways? I assume as long as the signals can be seen it's no different than travelling at night?

But I'm just a layman, please educate me!!
 
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ComUtoR

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Fog has not been a problem in my experience. We are on rails :)

Drive it like you stole it.
 

2Dogbox

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As drivers we are expected to drive to the linespeed during fog where possible. This is why there are no train delays.

We have route knowledge to enable us to drive knowing where we are and where the signals will be, although its not always easy. Some of the routes I drive where we still have absolute block the signals can be very difficult to see so you are relying on a "feel" for where you are really, the same applies to knowing where to brake for stations etc. You have to be very alert and very cautious at the same time. Not my favourite weather condition at all!

I had the full house one day last week; darkness, fog and low-adhesion with light rain.
 

Howardh

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In really heavy fog, could a driver sail past a station where s/he was supposed to stop?
 

61653 HTAFC

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There's occasional slight delays caused by reduced signal sighting I think, but often these minor delays can be made up on stretches where visibility isn't compromised so much.
 

Cherry_Picker

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In really heavy fog, could a driver sail past a station where s/he was supposed to stop?

It's probably been used as an excuse in the past but I wouldn't accept it in my depot. Train driving is preemptive, it has to be given the unresponsiveness of the controls. On a high speed railway, broadly speaking, if you can see something you need to stop at then the chances are you've left it too late to put the brakes on.

Drivers will have marker points for stations. Those markers tend to be points which you can still see even if it's foggy and dark outside. A signal a mile from the station, an overbridge, a tunnel (etc). It would be foolish to say that driving a train in thick fog doesn't affect a drivers behaviour but rail travel is the least affected means of transport I can think of.
 

scott118

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In really heavy fog, could a driver sail past a station where s/he was supposed to stop?

Only if they have misread their stopping pattern. A driver will know their location, by signals, braking points, and the sound of their train crossing over points, bridges etc, given their intense knowledge of their said route...

Driving in fog shouldn't make a difference. Leaf fall/low rail adhesion can be more unpredictable.
 

jopsuk

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Presumably though if in a driver's professional judgement they do not feel it is safe to drive at line speed the correct course of action is to reduce speed to that which they feel is safe (and fill out the paperwork to explain this later)?
 

Starmill

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Some trains were reportedly delayed last night by fog between Hull and Goole / Selby, but some sources attributed this to 'poor rail conditions'. I wouldn't know if fog comes under this or not but suspect not, and it might actually have been a mix of leaves and light rain? Dunno.
 

LNW-GW Joint

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Fog is what AWS is for.
You get an audio indication of the signal ahead, whether you can see it or not.
Writing this sitting in Newport station, on time despite 140 miles of thick fog through the mostly manually-signalled Marches route from Chester.
Impressive.
 

HarleyDavidson

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You shouldn't have any difficulty whatsoever driving in fog, when you do your routes, you're assessed and when you sign on the line, you're saying that you are competent to work over that line in all conditions.

I had to do several sets of empties last night and whizzing along with one set, found 2 yellows, put the brakes on and went into a slide at 65 mph, slid past the single yellow doing about 30 and when I came around the next curve gotthe bell to say that the next signal was green! :roll:

Couldn't see it though, but I wasn't fazed by not seeing anything. I can do the ton and not get fazed at all by not seeing anything.
 

A-driver

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The only real difference fog makes to driving is that you are braking relying on line side features close by to tell you how close you are to a platform rather than using depth perception to judge approach speed. Some locations where there is absolutely nothing around (ashwell and modern or meldreth for example) will see very minor delays as trains will generally brake faster as you are reliant on seeing the platform-absolutely nothing else to use to judge your distance from the platform. But the delays this can cause will be minimal. Also approach control signals can be a bit slower as rather than seeing it clear a quarter of a mile away you will have to treat it is red until you can see it (which can be as close as a few meters away).

Obviously should you become disorientated then you would slow down until you regain your bearings but you will know the road well enough to know 'ah, I've just gone under that blue bridge' or 'there's that bit of fencing with the funny graffiti on it, I need to start braking for the station about now'.
 

Antman

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In really heavy fog, could a driver sail past a station where s/he was supposed to stop?

Some drivers don't need fog to do that;)

I was driving on the M20 yesterday and it looked odd seeing Eurostars on HS1 going at full pelt through thick fog, I know that they have incab signalling and I'm sure it's all perfectly safe but some passengers might be a bit nervous:o
 

A-driver

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Some trains were reportedly delayed last night by fog between Hull and Goole / Selby, but some sources attributed this to 'poor rail conditions'. I wouldn't know if fog comes under this or not but suspect not, and it might actually have been a mix of leaves and light rain? Dunno.


Fog often causes poor rail conditions as its moisture. Also, this time of year heavy fog is very common but so are poor rail conditions. Look at most TOCs Twitter feeds at the moment and you will see comments from the public claiming fog is causing delays (hilariously funny tweets like "my train is delayed, must be wrong type of fog").
--- old post above --- --- new post below ---
In really heavy fog, could a driver sail past a station where s/he was supposed to stop?


Of course they could but it would still be their incident. Even if the station has a power cut at night making it impossible to spot due to no lights a driver should still know where they are well enough to stop correctly in the platform.
 

furnessvale

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Some drivers don't need fog to do that;)

I was driving on the M20 yesterday and it looked odd seeing Eurostars on HS1 going at full pelt through thick fog, I know that they have incab signalling and I'm sure it's all perfectly safe but some passengers might be a bit nervous:o

Not half as nervous as I was one time, landing at Zurich airport in thick cloud. Didn't see a thing until a heavy bump told me we were on the tarmac!
 

lincolnshire

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Some trains were reportedly delayed last night by fog between Hull and Goole / Selby, but some sources attributed this to 'poor rail conditions'. I wouldn't know if fog comes under this or not but suspect not, and it might actually have been a mix of leaves and light rain? Dunno.

Well it was foggy on and off all day yesterday and into the night in this area, as its very close to the River Humber and flat land.
As a good bit of all this area is also semaphore signals so not the best of things to see in the fog and also the dark later in the day.

Driver route knowledge is a definite as signal are not at semi fixed distances in this area.
 

philjo

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There were delays last month on some of the GN morning services due to thick fog in the fens north of Ely. I think the issue was speed restrictions imposed due to the number & visibility of level crossings in that area.
 

Johncleesefan

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Last night was my first proper experience driving in thick fog at night through salisbury plains, quite weird but still did linespeed as route knowledge dictated where I needed to be shut off, braking and what speed I should be down to and where etc.
 

thenorthern

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Track circuits are a major advantage over roads in fog as even if visibility is poor the signaler can still control trains safely and know if there is a train on a certain line, something car drivers don't have. As others have said as well AWS and TPWS are useful in fog.

Occasionally though visibility can affect trains but its much less likely to happen than with road transport or at airports.
 
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All of this confidence from the train drivers amongst us is reassuring, and certainly matches with my experience that, generally, trains are not delayed in foggy weather.

It does make me think, though. I've been in a number of situations where there's been a fire near to the railway and the line has been closed because of smoke drifting across. (The locals around here just *love* to set fire to each other's scrap yards and such...)

If visibility is not such a big deal and fog doesn't cause delays, why should smoke?
 

tsr

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All of this confidence from the train drivers amongst us is reassuring, and certainly matches with my experience that, generally, trains are not delayed in foggy weather.

It does make me think, though. I've been in a number of situations where there's been a fire near to the railway and the line has been closed because of smoke drifting across. (The locals around here just *love* to set fire to each other's scrap yards and such...)

If visibility is not such a big deal and fog doesn't cause delays, why should smoke?

It may be due to hazardous materials eg. gas cylinders at the scene of the fire, which would require an exclusion zone. Also, trains are not completely airtight so a large amount of toxic smoke being drawn in would be quite bad for the passengers and any aircon - even if it is just very unpleasant rather than of a lethal quantity.
 

ComUtoR

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If visibility is not such a big deal and fog doesn't cause delays, why should smoke?

Smoke is an unknown. Often there is smoke but where the fire is may have not been reported yet. Trains may also be slowed to identify the precise location. A fire will also spread if un-contained that may pose a risk to the line so trafic is slowed, stopped or diverted.

I reported a small fire at Elephant a few weeks ago. That cost a few minutes in delays because of me first identifying the risk and then reporting to the Signaler.
 

al78

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As drivers we are expected to drive to the linespeed during fog where possible. This is why there are no train delays.

This wasn't true for me on Sunday morning when it was foggy. I was trying to get from Three Bridges to Hassocks and ended up waiting 10-15 minutes longer for a train than expected. The delay was sufficient that the train due after the one I intended to catch turned up first. Whether that delay was due to the fog or something unrelated I don't know, there was only one other train delayed at that time according to the information monitor.
 

scott118

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simply because the fire can be accelerated, by the movement of a train & the air it brings with it. Hence when there is a fire, trains are stopped in that location, to assist the fire crews that are dealing to contain it. The OHL is also switched off, to protect such crews who are wafting the water about. In such cases where containers are of danger, areas are evacuated, to protect those close enough to be affected....

perhaps you should have been watching Emmerdale a few weeks past...:lol:
 

LowLevel

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I think the only time I've known a delay due to fog was down to an issue that wasn't very obvious until you thought about it. The driver stopped as normal at a very tall semaphore signal located in a cutting as the distant was on. The problem was the signal was so tall he couldn't see the arm in the fog so had to call the box to check if it was off.
 

whoosh

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The moisture from fog can make the rails slippery. Semaphore signals are harder to spot, with dimmer lights and are usually higher up (better to see in good weather, but worse in fog).

Not sure about Goole/Selby to Hull, but some routes with semaphore signalling only have AWS at Distant signals, leading to crawling around looking for the Home and Section signals in the fog, there being no audible warning of their approach.
 

dk1

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Lines like The East Suffolk suffer somewhat in heavy fog as it is littered with AOCL+B & ABCL crossings & the driver needs to see the flashing white. Apart from issues such as that it's line speed every time & rarely causes me delay.
 
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