Yes if travelling to Exeter/Paignton/Plymouth etc. from London the White Horse is visible especially if you sit with your back to the direction of the train. The White Horse is about 3 mins out side Westbury and 15 mins past Pewsey it cannot be seen from the tain when travelling between London to Bath

There is a car park, but you have to realise that this is a chalk escarpment leading onto Salisbury Plane. The horse itself is on an angle of 60 degrees maybe more. You will have to cross a small road, go over a style walk across a field with sheep poo, go down and through a kissing gate, and along a narrow path. You can get a view of the horse from the field but it is not as flat as you may want.

Sorry for the delay in replying. I've been at a conference for a week. It depends how close up a view you require but if you travel on the road from TROWBRIDGE to Westbury ( see a map) once you pass through Yarnbrook you will see views of the White Horse on the left, and you can pick your shot. The closer to Westbury you get along that road, the larger the view of the horse becomes. That would be my suggestion, but there are views further away if you want it in the context of nearby hills etc. Hope that helps

This question was asked some time ago but for anyone else going to the White Horse the answer is No. You would need your own transport, or walk ( steep climb) or get a taxi