I'd love to be able to travel the 20th Century Limited when it was the epitome of first class travel or the Empire Builder with its domed cars. Still, I would be sorely tempted to go back to the post WWII era which many consider to be the the pinnacle of passenger train travel.
So many things we take for granted we would have to do without. Or maybe your favorite era predated TV so your home entertainment device would be your radio. Would you give up your Hi-def big screen TV in favor of a little black and white set with rabbit ears and a fuzzy picture and only 3 channels to choose from (This one would be tough). Would you be willing to give up your smart phone in favor of a rotary phone plugged into a wall? (I would).
If it were possible to travel back in time to whatever time period you thought was the golden age of railroading, who would do that if you could only travel back in time and would have to live the rest of your life without so many modern conveniences we take for granted today.