In the 1800s, it was important to shoot fast and ride faster. If you were an outlaw, you had to know how to make a robbery and get away with it as well. If you were an officer, you had to think like the outlaws and follow where they went.
https://leb.fbi.gov/articles/additional-articles/from-the-archives-railroad-crime-old-west-train-robbers-to-modern-day-cargo-thieves

Allen Pinkerton was the first railroad law enforcement officer. In the 1860's, there was an increase in the number of railroad law enforcement officers. Pinkerton suggested the idea of burglar proof safes on all express cars. He came up with the idea of a heavy safe, so that no outlaw could get into it. The only way to get into the safe for outlaws was a large amount of black powder, or dynamite.
https://leb.fbi.gov/articles/additional-articles/from-the-archives-railroad-crime-old-west-train-robbers-to-modern-day-cargo-thieves

Sam Bass and "The Collins Gang" stole roughly $60,000 in 20-dollar gold pieces. This attack happened in Big Springs, Nebraska against The Union Pacific. The "Collins Gang" was later renamed the "Collins Crew".
https://leb.fbi.gov/articles/additional-articles/from-the-archives-railroad-crime-old-west-train-robbers-to-modern-day-cargo-thieves

The "Hole-in-the-Wall Gang" struck a robbery on a Union Pacific train near a site at Carbon, Wyoming. A few days latter, it was said that the gang killed two posse members; a deputy sheriff from Rawlins, Wyoming and a Union Pacific detective. The detective was in the middle of a mission to find the prosecutors.
https://leb.fbi.gov/articles/additional-articles/from-the-archives-railroad-crime-old-west-train-robbers-to-modern-day-cargo-thieves

"Kid Curry", "Butch Cassidy", and "The Sundance Kid" made a bold attack on the Union Pacific Overland Limited and forced them to detach the express car and move it away from the passenger cars. They blew up the car which destroyed the entire express car itself. Then "The Wild Bunch" was being chased down by "The Rangers". They chased them on horseback for miles. Outlaw members met their deaths in the following places; Kansas, Missouri, Texas, Utah, Colorado and South America.
https://leb.fbi.gov/articles/additional-articles/from-the-archives-railroad-crime-old-west-train-robbers-to-modern-day-cargo-thieves

The gang leader, Harvey Logan was arrested in Knoxville, Tenn. in 1902. He escaped in 1903 and met his last robbery on June 7, 1904. He was accompanied by two masked men. The next day Logan was wounded and reportedly took his own life.
https://leb.fbi.gov/articles/additional-articles/from-the-archives-railroad-crime-old-west-train-robbers-to-modern-day-cargo-thieves

In 1974, theft losses from rail shipments were $15.2 Million. In 1975, the losses rose to $20.7 Million. Shipments worth thousands would be loaded on one coast and transported across the Country, being protected by a small and fragile seal. https://leb.fbi.gov/articles/additional-articles/from-the-archives-railroad-crime-old-west-train-robbers-to-modern-day-cargo-thieves

The U.S. Secretary of Transportation offered help to the railroad officers, including leadership, guidance, and technical assistance. The officers obviously accepted the help, and today, they still continue to keep the railroads safe.
https://leb.fbi.gov/articles/additional-articles/from-the-archives-railroad-crime-old-west-train-robbers-to-modern-day-cargo-thieves

Railroad officers have joined with Federal agencies, State and local officials. They have also joined with National Cargo Security Program (NCSP).
https://leb.fbi.gov/articles/additional-articles/from-the-archives-railroad-crime-old-west-train-robbers-to-modern-day-cargo-thieves

Today, railroad officers are still protecting the trains. If you ask for one, you will be directed to the officer(s) of that railroad. Usually the land between major terminals are supervised the most.
https://leb.fbi.gov/articles/additional-articles/from-the-archives-railroad-crime-old-west-train-robbers-to-modern-day-cargo-thieves