1. Air-conditioning system in a railway car ensures a constant supply of fresh air in hot weather and heating the entire saloon in cold weather, doesn`t it?
2. The Trans-Siberian Railway is divided into six railways in Ural, Siberia and the Far East, didn`t it?
3. George Pullman became well known for luxury sleeping cars called Pullman cars in his honour, didn`t he?
4. These express trains will proceed to the final destination without any stops, won`t they?
5. Both direct and alternating current can be used on electrified railways, can`t they?
6. Powerful track-laying machines have been developed for the building of railroads, haven`t they?