this is from irfca, in case you are interested
Q. Are there rail connections to China or Burma (Myanmar) from the northeast of India?
A. At present, none. (And there have never been any in the past during British rule either.) In the northeast, going up the Brahmaputra valley, the Indian rail network comes quite close to China. It also comes near Burma at two places, though there are considerable gaps before the actual border is reached. The nearest Indian railhead to Myanmar is Lekhapani at the end of the (newly...
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converted) broad gauge branch line from Tinsukia Jn). (Passenger services currently terminate at Ledo. There used to be passenger service until Lekhapani in the 1970s. It is said that there are occasional special services between Ledo and Lekhapani for colliery employees.) On the Myanmar side the nearest railhead is a few hundred kilometres south-east of Lekhapani at Myitkyina. There are considerable difficulties in any proposed connection to China from here even though this is very close to the international border between India and China. Both to the north and to the east the territory on approaching and entering China is very difficult and mountainous. Incidentally, the old Ledo Road (also known as the Stilwell Road for Gen. Joseph Stilwell, commander of US forces in the area during the Second World War), which provided a war time connection between India/Burma and China started here, at Ledo, and conected through many winding mountain passes with China's Yunnan province. The other possibility for connecting to Burma is from Jiribam on the Assam-Manipur border at the end of the MG line from Badarpur Jn. and Silchar. However, the entire state of Manipur has to be traversed before the border is reached at the twin towns of Moreh (India) and Tamu (Myanmar). On the Myanmar side, the rail network does not currently extend to Tamu, but would have to be extended from Kalay, 83km away. [1/06] There is a proposal being considered by India and Myanmar to construct the Jiribam- Imphal-Moreh line in India, and the Tamu (Moreh) - Kalay - Segyi line in Myanmar, along with rehabilitation of the existing Segyi- Chaungu Myohaung line in that country. [8/07] RITES is conducting a feasibility study on this link. In both cases the connecting railway lines, if built, would have to cut paths across some formidable mountain ranges, not to mention the Chindwin River and thick tropical jungle. These
deterrents are probably what prevented such rail connections from being built in the past. Further to the South, Bangladesh Railways also comes close to Myanmar in the Chittagong area. But then come the Hill Tracts followed by the daunting Arakans. A railway line that closely follows the coast may be one possibility here. All railway lines in Myanmar are meter-gauge lines, reducing the value of a cross-border link because of the need for transshipment of freight from the main BG Indian network. There has also not been any political desire for such a link. (Although it has been suggested by some railway authorities a few times in recent years that the railway lines in Tripura (which reach until Kumarghat) could be extended into Myanmar and further south.)