No, through GATE you can't apply for the job in Indian Railways. There are 2 ways to get the job in Indian Railway either by UPSC or RRB's. UPSC's will give you Group-B(Gazetted post) with the increase in grade pay and promotion after every 4-5 years. However, with RRB you will get Group-C (Non-Gazetted post) with an increase in Grade Pay after 10 years and without any promotion.

 

So, it's better to prepare for UPSC exam to get a job in Indian Railways or for GATE exams which offer you job in various PSU.

 

Here you can find complete information about PSU recruitment through GATE :

https://engineering.careers360.com/articles/psu-recruitment-through-gate 

All the best!