The roughly 1,000-mile route links Quetta with Pakistan's other major cities, and railway officials say trains and infrastructure there have suffered at least 27 attacks in 18 months.
The latest attack, on 13 February, was witnessed by a New York Times reporter and photojournalist Asim Hafeez while travelling from Quetta to interview passengers.
Despite repeated hijackings, bombings and derailments, the train remains a vital lifeline in Balochistan, where separatists target it as a symbol of the Pakistani state.
As attacks escalate on the Jaffer Express, is Pakistan losing its decades-long battle for Balochistan?
How did Baloch rebels acquire US weapons and drone technology to cripple a key national railway?