The 999 is built to resemble a C62 Steam Locomotive while the passenger cars resemble the Suha 43, Moha 51, and Ohka 61 models. While the number of passenger cars vary by appearance, they usually average to about ten with the observation car on the tail of the train. Interestingly, the 999 is the only Galaxy Super Express that has a locomotive appearance compared to its more ultra modern bullet train-like contemporaries. Maetel says that this is so passengers recognize the appearance since the passengers tend not to come back after being dropped off.
The 999's locomotive front does not require a crew or engineer as it possesses a sophisticated AI that allows it to operate itself while following the regulations of the Galaxy Railways. The AI system also has a bit of a prideful side as it boasts itself the fastest of the Galaxy Super Express trains. Other type of emotions also exist as seen with its conversations with the Conductor. The engine also evokes a traditional steam boiler but is much more efficient and uses an alternative means of producing power while allowing anyone to enter the engine room.
The 999 primary voyage is a year-round trip from Earth to the Andromeda System. Because of the nature of the journey and the Andromeda Galaxy being the primary domain of the Machine Empire, most passengers are not accounted for with the responsibilities handled by the conductor. Once a passenger has reached their destination, they can never go back on the train. Maetel however is a special case for her job as was Tetsuro Hoshino when he needed to be evacuated. Also with the disappearance of the terminal station, by Eternal Chapter the old rules and services have become obsolete with the 999's usual services on hold.
The 999 features several cars that depending on the media have been brought up or mentioned.
Exists on the tail of the 999, used to look out and see the many sights as the 999 departs from its port. It is often destroyed or badly damaged in some of the series it appears in.
Limited express cars that are used to imitate newer generation models of trains complete with reclining chairs, fluorescent lamps, and an air conditioning duct. They are often colored green from the outside to differentiate from the other cars.
Second class cars that feature 4-seater box seats that is usually where Tetsuro and Maetel are usually at.
A seldomly seen that features beds and blankets and lack division compared to the seating cars.
A car that features box seats around tables that opens at 8 o'clock (AM and PM). A special cooking device allows passengers to get any type of food they like, which in the words of the conductor are not synthetic duplicates but genuine food items. Since there is not much staff and the waitress was the only other occupant, it is often speculated that the Conductor is the one who cooks the meals.
A car that features a library with domino-stacked bookshelves and feature items including newspapers. It has only appeared in the anime and was only mentioned in the manga.
A medical room used to nurse the injured or ill.
In times of emergencies, this car is used to deal with threats including space pirates. The car is equipped with a black hole cannon in the form of a turret that features twin guns and three barrels on each gun that are equipped on different sides of the car. Compared to the rest of the 999, this car has a more futuristic appearance and is even operated by a separate artificial intelligence that speaks through a robot.