The Dorgesh-Kaan Keldagrim Train System is an underground railway system created between the cave goblin city of Dorgesh-Kaan and dwarven capital Keldagrim before and during the Another Slice of H.A.M. quest. It is accessible after the quest is complete.
The railway system is unique compared to other methods of transportation in RuneScape in that the train does not immediately take off when the player clicks the vehicle or the associated personnel, but acts more like a real-life Metro system in which the passenger walks into the train and after staying in the compartment for a while the train takes off. A short cut scene is displayed during the trip, and the player will then arrive in the opposite city's station.