Sometimes you travel with pets if you need to move in city in trains.There are different laws, guidelines and policies which vary from country to country and also every transporter and train services have defined their own travelling rules for pets. So before travelling, you must be disseminate yourself by government laws and then ask for the procedures of the train service you are planning to travel. Some of train services do not allow the pets on board along with the passengers.
Many of intra-city trains and subways in US allow carrying small pets but leashed and well fastened or kept in carriers. Pets, specially dogs must be muzzled for security reasons. However in European countries like France, Germany and Italy, pets can travel on most of the trains. Basic requirements of all service providers are either pet are well leashed with harnesses and or kept in carriers. Some of the train operators in Great Britain do not allow carrying pets on board.