>>1091997In my masters program people come from a large variety of majors. Many of them had unemployable bachelors (music, history, psychology, etc.) and earn their masters a few years after graduating undergrad so they have useful skills. Having a relevant undergrad can certainly help to secure an internship during your masters program but most employers aren't too concerned about undergrad if you have your masters.
There can be a big difference between a masters in planning and being a transport engineer. You should look into the difference between being a planner and an engineer to make sure you get into the appropriate program for what you want to do. Engineers can do some planning skills but generally planners can't do engineering work.