Before I make this post I think I ought to make a disclaimer state that I've
NEVER been either of them, nor do I know anyone personally in either occupation. Nevertheless, I've looked up information for both of them beforehand out of interests, so I think I might know quite a bit about both the roles to give at least some useful information.
I know that train drivers are given 2 years to train for their jobs, maybe more, and that is usually with the TOC they are working for. Airline pilots on the other hand could spend decades learning to fly an aircraft, all of which comes out of their pocket if I'm not mistaken. Training for both jobs are very specialised in that the skills you learn won't be very transferable to unrelated careers, especially in the case of a train driver. I mean let's face it, the ability to drive a train won't assist you very much in getting unrelated jobs. I mean qualities such as concentration and customer service might, but you can get that from other careers too.
Lifestyle wise though, both can involve unsociable working hours, but it seems like with a pilot you can pretty much kiss any social life goodbye with only rare exceptions. Shift work with train driving might be a pain, but you can work around it with understanding friends and planning ahead with your rosters. For a pilot though, the end of your shift probably ends in a foreign country, and so you need to plan much more meticulously so you are both home and not due out the next few days.
Sleep patterns can also be disruptive for a train driver because of the shift work, such as going to bed at 19:00 for a start at 03:00, which I imagine is a problem especially in summer with daylight hours increased all the way to at least 22:00 hours. Humans are not evolved to sleep efficiently during daylight hours unfortunately, but there are ways around it. The thing is, it can be very tricky getting efficient nights of sleep as a train driver, and it's especially problematic if you have issues like insomnia. It takes a lot of commitment to stay with it despite potential for poor quality sleep. If you go to work tired, you can be putting many passengers at risk, and if you fall asleep at the controls you probably can expect serious issues to arise. It asks for quite a lot if you ask me.
With a pilot though, instead you get the luxury of jet-lag, and for a rookie this could very well be an issue when your body is ready to sleep, but because you might've landed in Hong Kong after a long flight from Manchester you'll be 8 hours ahead. If you fall asleep at this time, you'll be left in the dark hours when you wake up because everywhere will be out of action. It doesn't take long to get use to setting a new clock, but if you're travelling again in the next few days you will have to do it all over again, and if it causes sleep issues you will inevitably get cranky and lose energy. Still, unlike a train driver, you might be able to get sleep on a plane because of both the co-pilot and auto pilot, and I think on long haul flights there will be some crew swaps in the middle of the journey.
Salary wise, both pay pretty handsomely if you work with the right company. In regards to a train driver, some of the intercity operators like Virgin Trains offer up to £63 per annum, and Eurostar offer even more. It's not even unknown for drivers to make £70k so I've heard. The job might ask a lot with responsibilities and sleep, and requires certain qualities from you, but it certainly pays you well for it. Even smaller regional operators like Northern can offer around £35k, which is still generous in today's world.
Airline pilots though can be paid a very handsome sum of money for the right company. For example, Emirates pays some pilots 50k AED per month (over £10k). That could add up to over £100k per annum, and as such the money really does talk in this case. You might not like the sleeping hours or jet-lag, but you'll be laughing all the way home on payday. Having said that, some airlines offer much lower quality of work, and I've heard some very bad stuff about RyanAir salaries to the point where they learn to train with them, then when the opportunity arises they make a break to British Airways or Virgin Atlantic because it's that bad.
Job security would probably go to a train driver. If a railway company goes bankrupt under the current system, then another operator will be stepping in even if it's the DfT's so-called operator of last resort. You won't lose your job between franchises, and the unions are very serious when it comes to train drivers. If you lose your job, you're very unlikely to go without a good package to take with you. Pilots though are more blurred area in my knowledge. When Monarch went bankrupt I imagine many pilots lost their jobs, and it was only thanks to operators like Virgin Atlantic offering some other careers for them that some were able to keep their flying careers. But with airlines it's all open-access, so if your employer goes bankrupt, you're gonna have a bad time and uncertain future. So to go over my points in a TL: DR scenario...
- Training: Very specialised in both cases, though with a train driver you will only spend around 2 years for free training. As a pilot, you could be paying a lot for up to decades in the case of aircraft training.
- Lifestyle: Both are unsociable working hours and can cause sleep problems. As a train driver you can manage rosters easier but can't sleep on the job, whereas a pilot has jetlag but can sleep on the plane at some point.
- Salary: For the right companies, the pilot pay is vastly superior to the best pay of a train driver, but the quality of work can vary greatly been airline companies whereas most train operating companies have better working conditions.
- Job Security: Train driver without a doubt. You are less likely to lose your job and will likely get a good package thanks to union regulations. Airline pilots pay better, but they are much more uncertain in regards to future conditions.
Ultimately, the jobs are what you make it, and if you really wanted to be a pilot and love flying, you could very much find it to be the best job in the world. Nevertheless, it would be foolish to overlook the downsides because they do have a massive effect in your personal life and even your health. If you don't take interest in either jobs, you won't have a good job and should stay away. Some other candidates might be passionate about the work but not get it because of someone who seemed more experienced but didn't really have much interest in the job at all. Whatever you chose, just be prepared for a long road of learning...