150 years ago, in the midst of the Civil War, President Abraham Lincoln made an attempt to bind a fractured nation by signing the Pacific Railroad Act. Two companies -- the Union Pacific Railroad and Central Pacific Railroad -- were tasked with building a rail line from the Missouri River to the Pacific Ocean, linking both coasts of the United States. Between 1862 and 1869, the two companies would take full advantage of government financing, cheap labor and a nation distracted by war. Though corners were cut and scandals were numerous, the achievement was tremendous: What once was a harrowing journey of six months now took just one week. While passenger rail travel in the U.S. now lags behind the high-speed railways of Europe and Asia, the train was king for most of the 19th and early 20th centuries. In honor of the 150th anniversary of the Pacific Railway Act, we take a look back at 10 great American passenger trains, from steam engines to streamliners. Union Pacific 119 On May 10, 1869, Central Pacific Railroad chief Leland Stanford used a golden hammer to pound a single golden spike into the ground, joining the tracks of the Central Pacific and Union Pacific railroads in Promontory Summit, Utah. Beside Stanford were two trains -- the Central Pacific's Jupiter, and the Union Pacific's 119. It was pressed into service by accident: Another locomotive was planned for the ceremony, but it couldn't make it to Promontory Summit after some bridge supports washed away in Colorado. No. 119 just happened to be the closest nearby train, and became part of history. That's a replica shown above: 119 was scrapped unceremoniously after pulling freight for more than 40 years. Photo: jshyun/Flickr

Overland Flyer Arguably the most important part of the transcontinental rail journey -- and the most difficult section of track to lay -- was the connection between Council Bluffs, Iowa, and San Francisco, known as the Overland Route. It included a 12-mile trestle over the Great Salt Lake complete with a mid-lake station (known appropriately enough as Mid Lake Station) and tracks over the Donner Pass covered in wooden snow sheds. In 1890, the Overland Flyer train was renamed the Overland Limited. Union Pacific still runs trains on the Overland Route, but the last passenger Overland Limited train departed in 1963. Photo: Library of Congress

Union Pacific "Big Boy" The largest reciprocating steam locomotive ever pressed into service, the aptly named Big Boys built between 1941 and 1944 had two sets of eight drive wheels, four wheels for stability up front and another four wheels in the rear. They were so long that they had to be articulated in order to make curves. Only 25 were built, but they were legendary: Most remained in service until the late 1950s, when diesel locomotives had become commonplace. Eight have been preserved, a reminder of the final days of the steam engine era. Photo: Sheila in Moonducks/Flickr

Union Pacific 844 Fans of PBS' Shining Time Station will recognize this one: Union Pacific's 844, the last steam engine that the company would ever order. Built in 1944, it's never actually been retired. Instead, it serves as a "goodwill ambassador," running excursions for railway buffs and firing up the boiler to celebrate special occasions -- such as Union Pacific's 150th anniversary. Photo: Wildest Photo/Flickr

Union Pacific M-10000 Today, the snub-nosed "streamliner" is symbolic of the golden age of the railways. But in 1934, the M-10000 was revolutionary: all-aluminum, fully articulated and powered by an internal combustion engine. On a test run, it topped 100 mph and attracted crowds during the 1934 Chicago World's Fair. Though it ushered in a whole generation of streamliners, the M-10000's lightweight aluminum construction meant it wasn't up to the stress of everyday use. It was scrapped in the early 1940s -- supposedly to donate that aluminum exterior to the war effort. Photo: Advertisement

Burlington Pioneer Zephyr Though it came years after the M10000, the Pioneer Zephyr is what most Americans picture when they think of streamlined trains. The permanently linked, articulated train was built by the Budd Company and ran on the Burlington railroad between 1934 and 1960. The lightweight train featured stainless steel construction, and famously debuted with a "dawn to dusk dash" from Denver to Chicago. The trip took just 13 hours and five minutes at an average of 77 mph, and captured the attention of a nation that had been reluctant to travel during the Great Depression. Photo: Roger 4336/Flickr

Santa Fe Super Chief The luxurious flagship of the Atchison, Topeka and Santa Fe railway (just think of the Harry Warren and Johnny Mercer tune), the Super Chief brought stars from Chicago to Hollywood from the mid-1930s through the 1960s. In addition to its streamlined diesel locomotive and flashy paint job, the line was known for its plush all-Pullman sleeping cars and high-quality food from the Fred Harvey Company -- much of it sourced along the way, such as fresh-caught trout. The Super Chief was the only line of the era to offer direct service from Chicago to Los Angeles, a journey that took just under 40 hours. Photo: Advertisement

20th Century Limited The 20th Century Limited was America's answer to the Orient Express, an elegant yet understated service between New York City and Chicago that cost as much as a first-class air ticket on the same route today. The 20-hour trip began and ended with attendants quite literally rolling out a red carpet -- the origin of the now-common phrase. The most famous trainset to traverse the route was designed in Art Deco style in 1938 by Henry Dreyfuss, who also penned the Trimline and Princess phones for Bell, not to mention the iconic circular Honeywell thermostat. Photo: Alfred Eisenstaedt /Pix Inc./Time & Life Pictures/Getty Images)

GM Train of Tomorrow Under the direction of legendary designer Harley Earl, GM's Train of Tomorrow was a postwar effort at resurrecting American rail travel, which had already begun to suffer due to the advent of highways and airplanes. The central feature of the Train of Tomorrow was the Astra Dome roof, which allowed for uninterrupted views from an observation car. Such cars are commonplace on today's Amtrak trains, but it was a novelty back then. After three years of demonstration, Union Pacific ran the Train of Tomorrow on service between Seattle and Portland. Today, the train's last surviving car is at the Utah State Railroad Museum. It is described as being in deteriorating condition. Photo: Advertisement