Dear Student,

You are not eligible because the diploma or degree in engineering is required in basic stream or sub streams which are combination of basic streams i.e mechanical/mechatronics/manufacturing/tools & machinery/civil/cse/computer science.Also they have mentioned in which stream diploma should be or degree should be.You can check here the exam with details of stream which are eligible

http://www.rrbcdg.gov.in/uploads/RRB%20CEN%2003-2018.pdf