CHATTANOOGA, Tennessee (CNN) -- The train rumbled over the tracks toward the depot. Click, clack, click, clack, click, clack. A deafening whistle echoed across the valley. My 3-year-old boy's face lit up. He thrust his arms into the air, pumped his fists and belted out an exuberant "Choooooo! Choooo!"
Billy Drash excitedly waits for his first train ride, a venture on the Tennessee Valley Railroad.
I shouted out, "Chugga, chugga!" Then, I twirled around with excitement. Billy and I slapped high-fives.
This was our day. Our special Billy and Daddy Day! Mom and Big Sis were outta town. We plotted out a train ride for just this moment. Not one, but two. In Chattanooga, the land of the choo-choo.
"All aboard," shouted the bellman, his eyes peering out from his blue cap.
We hopped in line at the Tennessee Valley Railroad. "I want to sit in the back," Billy told me. This came as no surprise. I've ridden with the boy on Zoo Atlanta's tiny train probably over 500 times. About 490 of those times we've sat in the back. This was our first ride on a real train so it had to be in the back. Naturally.
We made our way through one train car and then the next. I kept my fingers crossed that no one had taken up camp in the very last seats. Billy sprinted. I tried to keep up as best I could. The back seats were empty. Satisfied, Billy plopped himself down. Send us your favorite father-son moments
According to the historical sign, our car was once known as a Jim Crow car -- a partition separated the races in the segregated Old South. In the 1950s and long overdue, the partition came down. People of all races enjoyed the revelry of the train on this day.
The train crept forward, inching along the tracks. Click, clack, click, clack. Billy stood on his seat as we went over a rickety bridge, over a creek and then through a tunnel. "Choo! Choo!" he said, squeezing my hand in the darkness.
"Who is Daddy's best buddy?" I said.
"Billy," he shouted.
"Who's Billy's best buddy?" I said.
"My Daddy's my best buddy!!!" he said. We squeezed hands even harder.
The train emerged from the tunnel and soon came to a halt. We got off and watched as the engine slowly got on a turnabout and turned around for the venture back. Billy's jaw draped the ground, marveling at such a feat. I clutched his shirt to make sure he didn't dart out in front of the locomotive.
With a mighty thud, the engine hooked back up to the passenger cars and ventured down the same tracks we journeyed on previously. This time, we stood outside on a platform during the tunnel. Billy grabbed his eyes after we got out of the darkness.
"The smoke hurt my eyes," he said, rubbing them. "OWWWWWWWWW!" It was a story he'd repeat countless times later in the day. To me, to his grandparents, to complete strangers. Anyone who'd listen really. He was OK in case you're wondering.
The train made its way back to the depot. Before heading on our way, I bought the boy a toy engine. ("Made in China," of course.) I loaded Billy into the minivan. We drove off to our next stop. The whole way there Billy screeched the sound of a train whistle, showing off his new engine and saying, "Daddy, look at me!"
The next train stop was known as The Incline Railway, the steepest passenger train in the world. The train heads one mile straight up Chattanooga's Lookout Mountain, a pitch of 72 percent at its steepest point. We sat in the back, of course.
It's hard to describe just how freaky this ride is. Billy took immense pleasure in it; I just tried not to look down, praying and cussing to myself for thinking this ride would be neat.
Finally, we made it to the top safely. Billy's grandmother greeted us there and took us to lunch. With a full stomach, we headed back down the Incline. When the train came to, Billy stood on his seat and shouted out, "That was cool!"
I pulled him closer, hugged him and held him tight. Summer's coming to an end. On Monday, he begins school five days a week.
But on this day, he's still my little boy. My best buddy. E-mail to a friend