The northern-most railway station in India is Sopore, at lat 34.26 N. The terminus of this line is Baramula, at 34.22 N
It seems unlikely that any line will be built further north. If the railway finally reaches Leh, it will still be at around the same latitude as Srinagar.
The northernmost station:
and the northernmost terminus:
You know that Ghum (near Darjeeling) is the highest station in India at 2258 M, which is on narrow gauge.
And Udagamandalam is the highest on metre gauge, at 2210 M.
The highest on broad gauge is in Kashmir, where the little-known station of Hiller Shahabad (between Banihal and Qazigund, just north of the tunnel) is at 1757 M
You may notice something odd about the Hindi inscription.
However, if a line to Leh gets built it will reach at least 3500 M which will be by far the highest point on the Indian Railways.
Our last stop today is a remnant of the old Sialkot-Jammu line, which must have shut down soon after Partition.
Here you can see the services listed in June 1944:
In the middle section, we can see that services were limited to two pairs of passenger trains between Wazirabad and Jammu via Sialkot.
The international border between Pakistan’s Punjab and the present UT of Jammu and Kashmir fell between Suchetgarh and Ranbirsinghpura, 15.86 miles from Jammu and 9.08 miles from Sialkot (approximately 25.5 and 14.6 km respectively). However, it appears that a part of Suchetgarh town is in India.
The last station on the Indian side can still be seen:
You can just make out the station name.
The history of this line after partition is not properly documented. Probably services would have stopped shortly after partition, and the rails on the Indian side would soon have been pulled up as the route was not useful. Meanwhile, the Indian BG network crept up from Pathankot to Madhopur (Punjab) and Kathua, reaching the new Jammu Tawi station in 1972.