By Paul Anderson
BBC correspondent in Islamabad
Pakistani and Indian officials have agreed on principle to reopen a second rail link between their two countries.
A rail link between Delhi and Lahore was restored in January
Extensive work will be required on the 130km (93 mile) stretch which has been idle for nearly 40 years.
Officials said the agreement was a positive start to the second phase of "composite dialogue" between the nuclear-armed neighbours.
The aim is to resolve numerous disputes between the two countries, including the Kashmir question.
Last month, Pakistani Prime Minister Shaukat Aziz met his Indian counterpart, Manmohan Singh, to try and ease rising tension over the lack of progress on Kashmir.
However, officials gathering in Islamabad did not provide a timetable for restarting the service linking Pakistani province of Sindh with India's Rajasthan.
The service was halted after the Kashmir war of 1965.
People hoping to use the service might have to wait a few years.
There is no track on a 10km stretch and the rest of it badly needs repair.
Pakistani officers check rail tracks for explosives
In the meantime, people wishing to visit families torn apart by partition in 1947 will have to use the bus or the only other rail link, re-opened earlier this year.
The talks mark the resumption of dialogue between India and Pakistan, which covers a giddying range of disputes, accumulated in more than 50 years of war and mutual hostility.
Over the next month, officials will cover territorial and water disputes, and seek agreement in areas like trade, travel and nuclear and conventional arms.
The key issue, though, at least for Pakistan, is divided Kashmir, and towards the end of this month senior foreign ministry officials will meet in Islamabad to discuss how to proceed.
All eyes will be on the signals that emerge. The past few weeks have seen both sides return to recrimination and accusations of poor faith.
Pakistanis complain that India has failed to match their leaders' readiness to compromise in the interests of a final resolution.
India rejects Pakistan's demand for speed, saying that the resolution of long-running disputes such as Kashmir requires time.