The Khojak Tunnel (aka Sheilla Bagh Tunnel) is a 3.91 kilometres long railway tunnel located in Killa Abdullah district of Balochistan (Province of Pakistan), near Pak-Afghan border at Chamman. It is located 6381 feet (1,945 metres) above sea level and was built as part of the Sind Pishin Railway.
1891 The tunnel was constructed under the Khojak Pass and remains one of the longest tunnels in South Asia, and the longest in Pakistan. It is expected to be surpassed by the 8.6 km Lowari Tunnel, currently under construction, in 2009.
It was featured on the old Rs. 5 banknote.
It was constructed in 3 years and it is so straight that a mirror can be used to reflect light at one end which is visible from the other.
The major railway line track laying and labour contractor was Waja Durra Khan Baloch from Karachi who originally migrated from Baho Kalat in early 1600s and got his first contract when British were working on Karachi Port. Later on he was awarded various railway contracts from Balochistan to Banglor and later Rangoon Burma. Later British awarded the status of honorary judge in Karachi city court and after his death a road named after him from badshi road to 8 chowk Lyari.