double decker carriages are becoming more common. The seats in most coaches until the middle of the 20th century were usually bench seats; the backs of these seats could be adjusted, often with one hand, to face in either direction so the car would not have to be turned for a return trip. The conductor would simply walk down the aisle in the car, reversing the seat backs to prepare for the return trip. This arrangement is still used in some modern trains. Dining car A dining car (or diner) is used to serve meals to the passengers. Its interior may be split with a portion of the interior partitioned off for a galley, which is off-limits to passengers. A narrow hallway is left between the galley and one side wall of the car for passengers to use. The remainder of the interior is laid out with tables and chairs to look like a long, narrow restaurant dining room. There are special personnel to perform waitstaff and kitchen duties. Lounge Lounge cars carry a bar and public seating. They usually have benches, armchairs or large swivelling chairs along the sides of the car. They often have small tables for drinks, or may be large enough to play cards. Some lounge cars include small pianos and are staffed by contracted musicians to entertain the passengers. These cars are often pulled in addition to the dining car, and on very long trains in addition to one or more snack or café cars. Café cars, such as the Amtrak café cars, are simpler, lacking window-facing seats, instead, rows of tables with facing pairs of bench seats, split by a food and drink counter. Lounge cars are an important part of the appeal of passenger trains when compared to aircraft, buses and cars; there is more space to move around, socialize, eat and drink, and a good view. Observation The observation car almost always operated as the last car in a passenger train, in US practice. Its interior could include features of a coach, lounge, diner, or sleeper. The main spotting feature was at the tail end of the car – some more modern US designs had walls of the car usually curved together to form a large U shape, and larger windows were installed all around the end of the car; earlier designs had square ends with an observation open deck (preserved stock