Can I take my granddaughter to her train platform when she travels to York? [closed]

Depending on the railway company and the station, you can buy a platform ticket.

National Rail Enquiries says

If customers are not travelling by train but wish to access the station platform - for example where there are ticket barriers in operation and they wish to assist someone onto the train or if they are a railway enthusiast - they may need to buy a Platform Ticket, depending on the discretion of staff.

Not all train companies still issue Platform Tickets but where they are still sold they cost ten pence (10p) and can only be purchased from the station ticket office. There is no charge to assist a disabled passenger to a train.

At other stations without barriers, unstaffed stations or at stations managed by certain train companies a Platform Ticket may not be required and customers are advised to check with the ticket office, where possible, before entering the platform. Each train company will advise their retail staff of their policy on Platform Tickets.

Part of the reason for a physical ticket is so that you can pass the automated barriers, but there is usually a member of staff available to open a gate manually (for large bags, wheelchairs, etc). If you don't have a ticket, engage with staff on the way in, so that they won't think you are a fare dodger on the way back out.

Note: this answer assumes the granddaughter is a child. The question is tagged "minors" but apparently that tag was added by an editor not by the original poster. If the granddaughter is an adult then your chances of getting let through the barrier are probably lower.

You probably can, assuming the child is of a suitable age for unaccompanied travel. At least one train operator claims a minimum age of 12, others seem to leave the exact threshold ambiguous.

As I understand it what you are not allowed to do is.

1. Board a train without a valid ticket (exceptions apply, but I won't get into them here).
2. Evade a ticket check (so no climbing over barriers, or forcing your way through them or tailgating)
3. Enter a "compulsory ticket area" without a ticket or permission from rail staff. Compulsory ticket areas are pretty rare on the UK mainline network though (more common on metro systems).

If there are barriers you should explain the situation and ask nicely you will probably be allowed through (though I don't think it ca be guaranteed). Some stations may give you a receipt or platform ticket of some sort to preset on your way back out.

I did exactly this in 2021, at Birmingham New Street, when my kid (on their 14th birthday) was travelling alone to Nottingham by train for the first time.

I was super polite to the staff at the ticket barriers, and they let me through. (It wasn't rush hour.) They helped me find, and explain to my kid how to find, the correct platform.

I then identified the guard on the train and introduced my kid, and explained what was happening. The staff were fantastic and everything went smooth.

I was the cringey parent who waved to them as the train pulled away =D

(There was another adult waiting for them at Nottingham.)