TUNNEL FEVER

You can feel the tunnel moments before you see it. The trail levels off slightly, and you click your bike gears down a notch, slowing to revel in the welcome drift of cool air and hint of mist. Suddenly, enormous wooden doors and a cavernous stone entrance, festooned with moss and lyrical with rivulets of running water, loom before you. You can almost hear the far-off moan of the last Chicago-Northwestern locomotive to pass this way.

No matter how many times I ride the Elroy-Sparta Bike Trail, the first sight of Tunnel No. 1, one of three railroad tunnels dug by hand through these hills in the 1870s, never fails to surprise and impress. The Kendall and Wilton tunnels (Nos. 1 and 2) are each ¼ mile long, and the Norwalk tunnel, No. 3, clocks in at ¾ mile long.

While recreational riders and serious cyclists have made the 32-mile-long trek a favored destination for decades, the Elroy-Sparta trail is also well-suited for families. If your crew can do it, an 18-mile ride will take you through all three tunnels in a day. But you could also tackle the trail three segments at a time over three days, an average of 6 miles each segment, and see each of the tunnels that way.

The last time I rode the trail in 2007, my daughter was just shy of 7 and I pulled her on a trailer bike. This time, she'd be running solely on girl power, riding a gearless 20-inch bike with coaster brakes. She wanted to see all three tunnels, visit all three towns.

I studied the trail map. By shaving off the Elroy and Sparta ends of the trail, we could cut 14 miles from the 32-mile ride. We'd start in Kendall at the historic train depot that serves as trail headquarters, stop in Wilton for lunch, proceed through Tunnel 2 and end the day's ride at Tunnel 3 and the town of Norwalk. My husband, who is not much interested in biking, would drive the "support vehicle" from town to town in case Lily-Anna couldn't make it.

Never underestimate an 8-year-old's determination and stamina. And never underestimate the allure of a tunnel. No sooner had we arrived at the Kendall depot when my husband caught tunnel fever and decided to rent a bike. He'd check out Tunnel No. 1, then return to Kendall to move the car to the next town. Lily-Anna tucked her stuffed animal, Lamby, into her plastic bike basket and took off -- iridescent purple and pink streamers fluttering from the handlebars.

Tunnel No. 1

The grade is no more than 3 percent anywhere on the trail. Generally, you get a gentle upward slope as you ride west out of town and toward a tunnel, and a gentle downhill grade as you exit each tunnel and cruise toward the next town. As the trail ascends into deeper woods and a higher vantage point over the fields, we stop frequently to rest and rehydrate. With those small wheels and no gears, Lily is working twice as hard as we are.

We whoop and holler as we feel the cool air of Tunnel No. 1 and stop for pictures and trail mix. I fish the flashlight out of the pack. You can see the light at the end of this tunnel, but you can't navigate by it, so flashlights are recommended. Cyclists are also asked to walk bikes through the tunnels single file to accommodate those passing in the opposite direction.

Shine the light around the rough stone walls and arched ceiling and you'll see soot from the steam locomotives that began running through this area in 1873. The route once handled 40 to 50 freight trains and six passenger trains daily. The last passenger train rumbled through in 1953, the last freight train in 1964.

We emerge refreshed, and Lily-Anna wants to continue the 6 miles to the next town. Dad heads back through the tunnel for his ride to Kendall. He'll load up his bike and meet us in Wilton.

Tunnel No. 2

When the Chicago and Northwestern used the route, watchmen were stationed at each end of the three tunnels and were charged with opening and closing the tunnel doors, among other duties. They holed up in shacks equipped with a telegraph (later a phone) for alerts to oncoming trains. Occasionally they slept through alerts, and although trains slowed to 15 miles per hour for the tunnel, the giant wooden doors would be reduced to splinters and a shower of iron rivets.

You get a hint of what it was like for them as you walk through Tunnel No. 2. Unlike the others, this tunnel has a series of arched "nooks" about 4 feet wide, 9 feet high, and 2 feet deep inset into the tunnel walls. If someone were stuck deep inside the tunnel with a train approaching, he could run for the nearest nook and flatten himself inside until it passed.

We each try out a nook. I shiver, but not because of the chill, damp tunnel air. On the other side, we again say goodbye to Daddy, who will go back to Wilton for the car and then drive to Kendall to return the bike. Lily-Anna is ready to proceed 6 miles to Norwalk and Tunnel No. 3.

I start calling her Tough Stuff.

Tunnel No. 3

Afternoon shadows lengthen in the woods around us and we ride side-by-side on the dappled trail. We pass fewer riders now. Finally, we pull into the rest area that signals we're almost there. Our arms get a workout as we push-pull the old green pump handle up and down to get spring water flowing into our bottles. We check out the red watchman's shack and the nearby stone flume -- an ancient-looking aquaduct built long ago to divert water from Tunnel No. 3.

Me and Tough Stuff disembark and begin our nearly-mile-long trek through the tunnel. We get splattered by the water that drips continuously from overhead; it feels good. The end of the tunnel is a speck of light in the distance. With no other cyclists around, the tunnel is a bit creepy. Lily-Anna starts chattering nervously to Lamby. I note that when you're a little edgy, it helps to sing a song. We go with the obvious. "I've been working on the railroad ... all the live-long day. ..."

Our voices echo weirdly around the dank tunnel. It takes several renditions and some speculation about "Dinah" to get through the tunnel. I give my kid an admiring high-five. She did it!

A couple hundred yards west of the tunnel exit, I buy her a celebratory ice cream sandwich at "Tunnel Tom" Cordner's tin-roofed refreshment shack. Cordner's Irish immigrant grandfather loved working on the railroad so much that he built his house next to the tracks a stone's throw from Tunnel No. 3. Cordner enjoys showing visitors old photos, including one taken of him at about age 4, standing on a stump as a passenger train roared past.

We head back into the tunnel toward Norwalk, where we're supposed to meet Dad. Tunnel No. 3 seems less scary on the return, and the day's heat has softened into lovely late-afternoon warmth.