Metallurgy

You should always ask the question in a lucid manner, kindly clarify your question.

You can continue your B.Tech or you can join any job.

Requirements vary from university to university. You must take GRE and TOEFL or IELTS exam depending on the country in which you want to pursue your MS.

ITI is the minimum eligibility to become a motorman.

Both are very different streams. You can opt for the engineering branch that you love the most and passionate about and analyze the future work conditions, scope and growth prospects before taking admission.
You can also opt for psychometric test comprising of aptitude, personality and career interest to clear confusion.

Chemical engineering has more scope but the competition is tough. However, metallurgy vacancy is very less in PSUs and competition is very less too. Best branches to get a job in a PSU are mechanical and electrical.