"I vowed to get easier to handle luggage for our next trip."
From one active 70+ woman to another....yes, this is the key.
What Pam said. I am in my late 60's and spend a month in Germany schlepping bags from train to train, and I will definitely be doing things differently next time. First, as Pam said, make sure your luggage is as light as possible. Start with a light suitcase and keep the contents as light as possible. If you use a backpack as a secondary item, keep it light, too. I thought a backpack would be easier than a tote, but mine was too heavy and it can affect your balance when you're trying to climb up onto the train while maneuvering your suitcase.
When you pack, just keep thinking that most of the people you meet will be strangers and do not care what you are wearing. Limit your outfits to no more than 3-4 and wear them over and over (merino wool garments are great for this). Wash them in the sink when needed and occasionally stop at a laundromat (or book a hotel or apartment with a washer).
Don't be afraid to ask for help. I found that many Europeans are more than happy to help someone who is struggling to get their suitcase up onto the train. Get to the train station early enough so that you don't have to rush around with bags, and make sure you download any available apps for the railway company you are using to check on last minute track changes and late trains.