The California gold rush brought Panama back onto the world stage in another quest for treasure. The fastest way to get to the gold fields was to cross at Panama, but it was hardly the easiest.

Thousands made their way by foot or mule across the 50 miles of the isthmus by way of the muddy, brutal Camino de Cruces, the same trail used by the Spanish during their own bout of gold fever. Untold others died attempting it, of cholera, dysentery, yellow fever, malaria, and the other dangers that made the Panama route notorious.

If a railway could be built across the isthmus, it would make the crossing faster and far safer for the Forty-niners who, not incidentally, would be willing to pay a small fortune for the privilege. A forward-thinking U.S. merchant named William Henry Aspinwall negotiated a treaty with Nueva Granada to build just such a railway shortly before the California gold rush began.

Though only 47.5 miles long, the railroad was an incredibly costly undertaking, both in dollars and lives. It was said that every railroad tie represented one worker dead from disease. That’s a wild exaggeration, but thousands did die building the little railroad through the jungle. In 1852, a cholera epidemic struck so quickly that workers died on the tracks, to be eaten by ants and land crabs.

So many died that the Panama Railroad Company started a lucrative side business shipping cadavers preserved in barrels to medical schools and hospitals around the world.

Engineers had to contend with the powerful Río Chagres, which could rise 40 feet overnight, and with obstacles such as the seemingly bottomless Black Swamp. When the railroad was completed in 1855, it included 304 bridges and culverts. The company was able to charge US$25 in gold for a one-way trip, a huge sum for the day.

The massive influx of foreigners on the isthmus, some of them rather rough characters, caused some conflicts. The worst incident occurred in April of 1856, when an allegedly drunk train passenger who had just arrived in Panama City grabbed a slice of watermelon from a black vendor and refused to pay for it. This sparked the so-called Watermelon War, a day of rioting that had racial, anti-American, and class overtones. It left at least 16 dead, almost all North Americans, and caused extensive damage to railroad property.