Do seniors get a discount on trains?

Excuse me, I was wondering if there is any special discount offered for senior citizens when it comes to train travel? I've heard that some public transportation systems offer concessions for the elderly, and I'm curious if this applies to trains as well. It would be great if you could provide some information on this matter, as I'm planning a trip soon and would like to make sure I'm taking advantage of any available discounts. Thank you in advance for your help.