Open the website of the regional RRB you applied through and look for the Junior Engineer cutoff link.
Cutoffs are usually released as a PDF with category-wise and post-wise marks.
Download the PDF and find the cutoff for your category and post.
Cutoffs are announced separately for the CBT-1 and CBT-2 stages.
Never trust cutoff figures shared on social media — use only the official RRB website.