What is going to be the MPS between SVDK and Srinagar section? I doubt average speed of 45 KMPH you have given is sustainable in that entire stretch of 188 KMs which is single line too. Currently avg. speed is pretty low for all trains between JAT and SVDK too.
You can speed up this imaginary train between Delhi and Jammu by 20 minutes easily, its a bit slow in the existing TT as JAT is terminating station, but will see a speed up once extended to Srinagar. Those 20 minutes you...
more... can add in SVDK-Srinagar section.