Some old articles from Railway Gazette regarding a unrealised 1960s scheme for a rail link from the Pakistan Railways railhead at Chaman to Spin Boldak, a short distance across the border in Afghanistan.
Spin Boldak is a major border crossing point, and it seems that railway extension plans have been talked about every so often.
20 May 1966
Talks between Afghanistan and Pakistan were held on May 4 1966 regarding building a railway to Spin Baldak. 
2 September 1966
Construction to Spin Baldak “is to begin soon”.
17 May 1968
Bad news: the Spinbaldak scheme, which was to have been financed by the US Agency for International Development, has been abandoned.
(clippings © Railway Gazette International)