Rejection of NOC by controlling officer on ground of shortage of Staff

Hii, i am working as SENIOR SECTION ENGINEER/TELECOM( pay level-8 IN 7th CPC, Grade Pay-4600 as per 6th CPC) in NORTHERN RAILWAY. i applie for the post of Engineering Associate(S&T) in NCRTC. This post is being created for the experienced employee from the central/state/PSU on Absorption basis by NCRTC. and equivalent to the post at PAY Level-8 in 7th CPC. I applied for the NOC to my controlling officer through proper channel. But my application for NOC has been Rejected on the ground of shortage of Staff.can NOC be Rejected on the ground of shortage of staff in railway as there is further no career progress in railway for Senior section Engineers. very limited posts are created in railway for the promotion of Senior section engineer at an interval of 2-3 year. please advice in my case whether the rejection of NOC is within rule or Not. what are the rules for rejection/deny of NOC on any ground. and please advice now after the rejection of NOC, what options are available further to me as per LAW to get NOC. Thanks MOHIT KUMAR SSE/Tele