In 1925, a donkey named Macario hauled a wagon up a narrow-gauge rail track on one of the most remote islands in the Caribbean, shaded by a makeshift canopy rigged over the car. The rails beneath his hooves were already crumbling -- twenty-two years old and never designed to last this long. Within two years, an automobile road would replace the tramway entirely, and Macario's daily commute would become a footnote in the industrial history of a place most people have never heard of. But for three decades, this improbable 1.8-kilometer railway was the only way to reach the Mona Island Lighthouse.
The engineering challenge was vertical. Mona Island's coastline is a wall of limestone cliffs, and the lighthouse sat on the plateau 37 meters above sea level. Getting building materials from ship to summit required a system that was part railway, part cave passage, part staircase. Ships unloaded cargo at Playa La Escalera, where a 70-meter incline powered by a steam cable winch hauled goods up to the entrance of Cueva Escalera. Inside the cave, a flight of stairs climbed through the rock to a station on the plateau above. From there, the second section of track -- 1.8 kilometers of narrow-gauge rail -- ran level across the flat island top to the lighthouse construction site. The two stretches of track were never connected; the cave itself was the transfer point.
A storm destroyed the loading facilities at Playa La Escalera, forcing operations to shift to Playa Pajaros -- five kilometers farther down the coast, a significant detour on an island with no roads. Then the hurricane of September 1921 tore off the roof of a lighthouse storage room and damaged both the kitchen and the tramway. A US Department of Commerce inspection in 1922 painted a vivid picture of the journey: after mooring through a narrow reef passage with onshore winds, visitors walked a mile-long path through cactus to reach the cave entrance. The incline ran at a 50-percent gradient. The plateau track derailed constantly because the rails, by then over two decades old, were disintegrating. The whole operation was held together by improvisation and the willingness of Macario the donkey to keep pulling.
The lighthouse itself was prefabricated -- designed and delivered by the French construction company Stapfer de Duclos & Cie. Because the components came from France, historians believe the tramway used Decauville portable track with a metric gauge rather than the imperial gauge common elsewhere in Puerto Rico. This was practical engineering: Decauville track was designed to be laid quickly on unprepared ground, exactly the kind of system you would want on a remote island with no existing infrastructure. The 16-meter lighthouse was completed and put into operation on 30 April 1900, its beam visible for 20 miles across the Mona Passage. Listed on the National Register of Historic Places in 1981 as Faro de la Isla de la Mona, the lighthouse outlasted the railway that built it by more than half a century.
The lighthouse tramway was not the only rail system on Mona. Other narrow-gauge lines served the island's guano mining operations, threading into coastal caves where bat droppings had accumulated for centuries into a valuable fertilizer. Most of those rails were removed over time, scavenged or carted away as the mining industry wound down. But traces persist. In Cueva del Lirio, a stretch of track still runs into the darkness. As recently as 1998, four-meter segments of rail sat in place inside Cueva del Diamante and several other caves -- rusted, half-buried, but stubbornly present. Construction of an automobile track began in 1927, and the lighthouse tramway lost its reason to exist. What remains is the kind of infrastructure that only reveals itself to those willing to bushwhack across a plateau or crawl into a cave: fragments of a system that once connected the sea to the light.
The Mona Island Tramway route runs across the flat limestone plateau of Mona Island at 18.09N, 67.85W. From the air, the lighthouse at the eastern end of the island is the most visible landmark -- a 52-foot tower on the plateau edge. The tramway route itself is not visible from altitude, but the plateau's flat terrain and the cliff edges where the incline once operated are clear features. Mona Island sits in the Mona Passage between Puerto Rico and the Dominican Republic. Nearest airport is Aguadilla's Rafael Hernandez (TJBQ), approximately 45 nm east. Best viewed at 2,000-4,000 feet to appreciate the cliff-to-plateau transition the tramway navigated.