Smith Tower Gatehouse: The Odd-Looking Castle Turret on the Enola Low Grade

The first time you see it, you do a double take.

Set just above the Enola Low Grade Trail in Martic Township, partially screened by trees at the top of a steep ridge, stands a round, turreted structure that looks wildly out of place. Its thick masonry walls and conical roof give it the unmistakable silhouette of a medieval watchtower, the sort of building you expect guarding a castle gate rather than perched above a railroad grade on a Pennsylvania hillside. Hikers slow their pace. Cyclists glance up as they pass. Most people wonder the same thing, even if they never say it aloud.

What is that doing here?

It is not decorative, and it was never meant to be admired. This is the Smith Tower Gatehouse, sometimes called a valve house, and despite its fairy-tale appearance, it existed for one reason only: to control water for one of the most demanding freight railroads ever built. What looks like a curiosity along a recreational trail is, in reality, a surviving control point from an industrial system that once kept steam locomotives moving relentlessly through the Susquehanna Valley.

To understand why it mattered, you have to understand the Enola Low Grade itself.

Built by the Pennsylvania Railroad between 1903 and 1906, the Atglen & Susquehanna Branch—better known as the Enola Low Grade—was engineered to solve a specific problem. Freight traffic was overwhelming the PRR’s passenger routes, and heavy coal trains struggled on steeper main lines. The solution was a dedicated freight corridor with a ruling grade of just one percent. That figure sounds modest, but in railroad terms it was transformative. A one percent grade means a rise of one foot for every hundred feet of track, gentle enough that massive freight trains could keep moving without helper engines, burning fuel steadily instead of fighting gravity and consuming water at predictable rates.

The Low Grade was designed to move weight, and it did so relentlessly. Long freights rolled through southern Lancaster County day and night, bypassing towns and stations, their crews focused on momentum and tonnage rather than scenery. Everything about the line served motion.

That motion came at a cost.

Steam locomotives burned coal, but they consumed water in far greater quantities. For every pound of coal shoveled into a firebox, roughly eight pounds of water were required to generate steam. On a freight road like the Enola Low Grade, where trains were heavy, frequent, and expected to maintain speed, water was not a convenience. It was the limiting factor. A busy division could consume hundreds of thousands of gallons in a single day, and if the water supply failed, the railroad failed with it.

Supplying that demand required an infrastructure most people never saw.

Above the gatehouse sat a reservoir capable of holding roughly 500,000 gallons of water, slightly smaller than an Olympic-sized swimming pool. From there, water fed the railroad’s supply network, ensuring that locomotives passing below would never outrun their most essential resource. When the system worked, it vanished into the background. Crews noticed only when it didn’t.

Down on the tracks, the payoff came at speed.

Rather than relying solely on trackside towers, the Pennsylvania Railroad built reservoirs directly into the hills above the line. Streams were diverted. Runoff was captured. Gravity did the rest. From these elevated basins, water flowed downhill through pipes to valve houses like Smith Tower Gatehouse, where it could be controlled, measured, and released into the system below.

The gatehouse was one of those control points. Its thick stone walls insulated critical valves from freezing temperatures and protected them from vibration and weather. The building’s solidity was deliberate. This was not a place for comfort or convenience. It existed to quietly regulate flow, day after day, without drawing attention to itself.

The Enola Low Grade was equipped with track pans and shallow troughs set between the rails, which were fed directly from the water system above. As a locomotive approached, a scoop mounted beneath the tender was lowered into the pan. At speeds of 30 to 60 miles per hour, water slammed upward into the tender in a violent rush, filling it in seconds. The process was efficient and violent. Done correctly, it allowed trains to take on thousands of gallons of water without stopping. Done incorrectly, it could tear equipment apart.

This was not a gentle system. It was an industrial choreography measured in tons, gallons, and miles per hour.

The gatehouse itself was only one piece of a larger operational village carved into the hillside. Nearby stood sidings, service areas, dwellings for railroad workers, and the Smith Tower dispatch structure that gave the site its name. That tower, once responsible for overseeing train movements through this stretch of line, is gone today, reduced to little more than a fragment of its brick chimney. The gatehouse remains because it stood slightly apart, built to last, its function hidden rather than visible.

An interpretive panel now stands along the trail, explaining what the structure once did, but even with that context, the scale of the operation is easy to miss. The reservoir above looks like a quiet pond. The gatehouse reads as a curiosity. Nothing about the scene suggests the volume of water that once surged through this hillside or the number of locomotives that depended on it every day.

Today, the Enola Low Grade is a popular 29-mile-long rail trail stretching across southern Lancaster County, beginning in Atglen in Chester County and continuing all the way to the Turkey Hill Overlook in Manor Township. The virtually flat route, through forests and fields, makes it the perfect place to walk, jog, or ride a bike. On this quiet trail, it is easy to forget that this corridor once carried some of the heaviest freight trains in the eastern United States. Smith Tower Gatehouse disrupts that illusion, standing as a reminder that this peaceful path was once part of a machine that never slept. It’s water, stored above the trail and released through locked stone walls, that made the entire system possible.

Planning Your Visit

Smith Tower Gatehouse can be seen from the Enola Low Grade Rail Trail approximately 0.7 miles east of the Red Hill Road parking area. The structure is on private property but visible from the pathway.

.

Uncharted Lancaster Podcast

Take an even deeper dive into the story with the Uncharted Lancaster Podcast in this Season: 1, Episode: 9: The Enola Low Grade: Iron, Blood, and Engineering Glory.

---

Adventure Awaits!

Never miss a new article by signing up for email updates below. Be sure to follow Uncharted Lancaster on Facebook or Instagram for exclusive content.

---

Learn More

📖 Learn about Lancaster County’s many unique places when you step off the beaten path with Uncharted Lancaster: Field Guide to the Strange, Storied, and Hidden Places of Lancaster County, Pennsylvania by Adam Zurn. This one-of-a-kind 239-page guidebook uncovers 56 fascinating sites, from the county’s very own fountain of youth to the oldest continuously operating short-line railroad in the western hemisphere.

Packed with history, local stories, and GPS locations, this book is your ticket to exploring the mysterious corners of Lancaster like never before. Whether you’re a lifelong local, a history buff, or just looking for a unique adventure, this field guide will spark your curiosity and send you exploring. Start your adventure here.

Resources

• A Perfect Freight Road Blazes West
• Servicing a Freight Road
• Water On the Fly
• A Stream for Steam
• RiverRoots: Enola Low Grade
• Remembering Lancaster County by Jack Brubaker
• Atglen and Susquehanna Branch
• Measuring Worth
• Enola Low-Grade Trail
• Enola Low-Grade Trail Trail Access Guide
• The Cost Of Labor | Constructing The A&S
• Workin’ on the railroad / A century ago, a monumental task began along the Susquehanna River
• The Atglen & Susquehanna Low Grade