More than 5,000 armed forces personnel travelled by train to London Waterloo before marching off to take part in the coronation.
Network Rail said it was the biggest movement of military personnel on Britain’s railways since Sir Winston Churchill’s funeral in 1965.
Members of the Royal Navy, Army, Royal Air Force and Commonwealth forces travelled to the UK’s busiest railway station on Saturday morning on board seven South Western Railway trains and two chartered West Coast Railways trains.
After leaving Waterloo, they marched over Westminster Bridge to assemble ahead of the coronation.
The military personnel are leading processions accompanying the King and Queen to and from Westminster Abbey.
Network Rail’s Wessex route director Mark Killick said: “We are delighted to have welcomed over 5,000 armed forces personnel to London Waterloo this morning in what is the biggest movement of military personnel by the rail industry since 1965.
“I would like to thank the many colleagues who are working exceptionally hard to ensure our customers experience smooth and pleasant journeys and I would like to wish customers an enjoyable and memorable coronation weekend.”
South Western Railway managing director Claire Mann said: “We are proud to support the armed forces in their ceremonial duties for what will be an unforgettable day for the whole country.
“I’m very grateful for the hard work and support of all of my colleagues who have made these special trains possible, and the additional services we are providing to Windsor & Eton Riverside for the coronation concert tomorrow.
“On behalf of all colleagues at South Western Railway, I wish everyone a happy coronation weekend.”
“For the thousands of soldiers, sailors and aviators from the UK and across the Commonwealth to arrive in London together by train before marching off to take part in this historic ceremony was a unique and special moment and my thanks go to all involved in making it happen.”