Can you be a train driver with glasses?

Often yes. Plenty of drivers wear glasses or contact lenses. Corrected eyesight is not automatically a no. Colour vision is the stricter question, and colour blindness is assessed as its own thing, not as “do you own a pair of specs”.

There is a medical. Eyesight, hearing, and general fitness are part of it. Standards exist for safety. They are not for a blog to paraphrase, and they are not whatever a forum decided last Tuesday.

Glasses and contact lenses

If your vision meets the standard with correction, glasses are usually the boring answer. Take the pair you actually wear. Do not sit the medical as a test of how well you can squint. If you are unsure, ask occupational health or your optician, not a thread.

Colour vision and colour blindness

Signals are coloured on purpose. Selectors care whether you can tell the aspects apart under the conditions they use, not whether you can name a colour in a well-lit kitchen. Some forms of colour vision deficiency are a barrier. Some are not. That is a medical judgement, not a personality one.

Do not guess from an online Ishihara screenshot. Do not hide a known deficiency on a form. Lying on a medical is a worse idea than the thing you are hiding. Ask the operator's occupational health if you already know you have a colour vision issue.

What the tests still are

The psychometric day is attention, search, concentration, and judgement. Glasses will not sit that for you. If the medical is not an obvious no, practise the battery so the scarce attempt is not spent on surprise.