The explosion killed at least 24 people and injured around 70, according to three provincial government and security officials.
The attack was the latest in a series of strikes on trains, security forces and infrastructure in the mineral-rich province that borders Iran and Afghanistan, where Pakistan has launched counterinsurgency operations after some of the deadliest violence in years.
The shuttle train was carrying passengers from Quetta's cantonment area to connect with the Jaffar Express long-distance train when the blast struck near a railway track in the provincial capital, Pakistan's railways ministry said in a statement.
The separatist militant group Baloch Liberation Army, or BLA, said in a statement to media that it carried out the attack and described it as a suicide bombing.
