The Koutetsujou (甲鉄城, lit. Iron Fortress) is a Hayajiro from Aragane Station. After crossing through Hayatani Station and stopping at Aragane Station, it was used to evacuate Aragane's survivors once the station was breached and overrun by Kabane.
The koutetsujou was first seen being attacked by kabanes, presumably going to Aragane Station.
The Koutetsujou looks almost like a steam locomotive. It is made almost entirely of heavy metal components and it has numerous ports and slits found along its body to allow the internal Bushi to repel any kabanes that have latched on outside. A master key is required to operate the Koutetsujou, which can be inserted in a keyhole in the crew compartment.
The locomotive recently acquired a new cannon after its successful passage of the Yashiro Station.
The locomotive is capable of running at high speeds (based on episode 1 the train seemed to move at about 90-100 Miles per hour).
The Koutetsujou is also an effective mower of kabanes that stand on the rail tracks due to what appears to be a razorlike plow at its front.
By looking at the tracks for the locomotive it is possible to believe that they're way to large for a normal locomotive as the standard gauge track for a locomotive in Japan is around 1,067mm (3' 6”). But for the Koutetsujou, it would be estimated to be around 5,500mm (18' 0").
While it is difficult to ascertain the locomotive's wheel arrangement due to the various side skirts covering the wheels, it is likely that it is a large articulated design - a Kitson-Meyer type, or something even more unusual.