Hi Dave:
Thank you for responding. So if you were an engineer operating on the main line, is there something besides the things I listed in the original post, where a radio communication may distract you? For example, we're expecting if an engineer was approaching a signal where he should see it all the way through, if a radio communication came in at the same time, he may stop looking at the signal and it could drop right before he goes through, and he/she wouldn't see it.
Any scenarios like a signals you mentioned below, where engineer should definitely take notice? How would a tunnel possibly fit into this? I'm not aware of what an engineer looks at in or around tunnels.
My apologies for the delay in answering your questions. My health has not been what I would have wanted these last few days. Considerably better now though, I'm glad to say.
My experience is of driving trains in the UK where radio chatter is considerably less than in the U.S. or Australia. In the UK, even if there is another (authorised) member of staff on the footplate with the driver (engineer), rules and ettiquette dictate that that person will fall silent and not distract the train driver if the train approaches a caution or danger signal or is enters a place where the train must be brought to a halt (stations, sidings, yards etc..) However, most British trains are single manned these days - but the principle still applies should anyone enter the cab environment. Furthermore, the driver in charge of the train would also ignore ANY and ALL radio calls until such time as his train had been brought safely to a stand or it was safe for him/her to respond to the radio away from all possible dangerous situations. Obviously, emergency situations could and would change priorities should it become necessary.
When approaching caution signals, a driver always has the signal in sight but not necessarily by looking directly at it. Peripheral vision comes into play, especially when there are various other activities going on in the immediate area. However, should that signal change aspect then the driver's full attention immediatley comes back to it and he/she will respond accordingly. Drivers place their absolute trust in signals - if they didn't they would never go above 10 mph - and as such, every signal conveys a message to a driver that he/she will do his/her utmost to never miss. No matter how many years you've been doing the job, a caution signal will make any driver "tune in" full on and be ready to respond in the appropriate manner. When approaching a danger signal, however, it is firmly fixed in the driver's vision at all times. Nothing else matters. To a train driver, a red signal is a brick wall! (And as they tell you in training here in the UK, anything on this side of it is yours. Anything on the other side of it belongs to the boss - and you don't want to be meeting the boss over this particular issue.)
When entering stations, drivers will scan the full length of the platform ahead of them for possible problems, e.g. hyperactive kids messing about and pushing each other towards the track as part of their tomfoolery, parcels, baby buggies or anything else potentially too close the platform edge to be considered safe or even potential suicidal people; as well as a multitude of other scenarios. After that quick scan, your main vison is then concentrated on roughly the area you will be bringing the train to a stop - but everything else remains in play too.
When approaching tunnels, several things come into play. Firstly, I want to know that the tunnel is still a tunnel, i.e. it hasn't suddenly become a cave. If I can normally see right through the tunnel then I'll be quickly checking to make sure that I can do on this occasion too. Instinct will also warn you if there is any unexpected change to the shape of the tunnel (sagging roof, bulging wall
). Your brain has logged a picture in its memory banks over numerous visits to the area you are now approaching and it's amazing how that picture can be instantly recalled when something is "not quite right." I also want to know that the tunnel mouth/portal is still in good condition with no bits falling off or hanging down? Are there any obvious signs of a landslide/slip or large quantities of water entering or flowing out of the tunnel? These are all observations made in seconds but done everytime without even thinking about it.
Once in the tunnel, vision is obviously extremely limited - especially if the tunnel has one or more curves in it. In the darkness you are on the lookout for anyone potentially working in the tunnel or walking through the tunnel (authorised persons would normally be aware of your presence and they would know where to safely stand but their lights/torches would be visible to you. Unauthorised persons usually end up as mincemeat and you generally only know that they were there at the last second or when you hear the "bump" as you knock them over.) Apart from the visuals, a driver would also be "looking out for" potential "wet beds" that cause severe bounce or drops that cause the loco to bottom out on the suspension, or any other rail defects that might become apparent. Once the exit to the tunnel is in view, your eyes are drawn to the light and you start to take in all the same sort of things that you looked for on your approach - as well as looking out for people or livestock outside of the tunnel.
Drivers are often very good at "looking cool" or giving the impression to onlookers that what they are doing is easy. Believe me, they are ALL switched on at all times. Lives depend on it. If you make a mistake with hundreds or even thousands of tons behind you, someone is going to get hurt (or worse) and number one candidate on the list is the man at the front!
Cheers
Dave