Similar to my story. I get off a commuter train and have a five mile bike commute. The first week I did it only two days, and felt wrecked. The second week I discovered a shuttle bus that would get me to within a mile, so I started taking that.

Now, a year and a half later, I race that bus.

My main reason for bike commuting at first was I didn't want to be putting 130 miles per day on my car. The bike made taking a commuter train more convenient. Now I do it for fun and fitness. Last month I did a Solstice ride where I commuted by bike after work, all the way to where I had parked my car to get on the train that morning; 54 miles. I made it with a half hour of daylight to spare.