The front of this post card shows a section of track leading to a tunnel in the Eagle River Canyon on the Denver and Rio Grande Western Railroad. That is what the caption at the bottom left of the picture says. The copyright on the bottom right says that the picture was taken in 1898. That doesn't mean that the post card is that old; or at least I cannot prove that it is that old. More on the age of the card at the end of this post.
The following information was taken from: www.drgw.net/info/TennesseePass
The first part of the Denver & Rio Grande line from Salida, CO, up to Malta was constructed as part of the narrow gauge extension of the Royal Gorge Route route in 1880. From Malta, what would become the Blue River Branch was run up to Leadville, and then up and over Fremont Pass at 11,330 feet. The branch then worked down the north/east side of the pass as far as Robinson. Another branch was extended north to charcoal ovens at Crane's Park, near the south side of today's Tennessee Pass. The objective was not to cross the Divide and reach points west (that goal having already been accomplished via Marshall Pass), but rather to tap the mining boom under way in Leadville.
The next year, 1881, was more of the same. The branch from Malta to Cranes Park was extended over the Divide at Tennessee Pass, and then down the Eagle River valley/canyon
Only just shy of a year after the Union Pacific-Southern Pacific merger, on 23-Aug-1997, the last through revenue train went over the pass. The train was OMIGV-19, a westbound unit taconite train with two units on the front and three in the middle. It departed Pueblo at 1125h and pulled into Minturn at 2005h. The last train over the top of the pass is questionable, but Denver Rio Grande Western 3075 went over the top from the west side on 23 Dec 1997 with two gondolas for Malta, running back light. The Malta Local continued to run from Pueblo-Malta until 9-Mar-1999, and beyond that only a few work trains have plied the east side of the pass.
Now about the age of the post card. This is one of my favorite post cards. I love and respect all post cards that are from the era when the only thing allowed on the back of the post card was the address. The sender had to be creative if s/he wanted to send a message and not just a picture. You can see at the bottom on the front of the card, John has written "On DRG Train May 8 - 06" So this post card is guaranteed to be 112 years old today. But keep reading; it may be older. It wasn't mailed until three days later in Spokane, Washington.
The printer of the card was the Detroit Photographic Company. Originally a printer of religious books and calendars, the Detroit Photographic Company Ltd. shifted production in 1897 when owners William A. Livingstone and Edwin H. Husher saw the potential in postcards. After negotiations with Orell Fussli, Detroit became the sole American company to license the Swiss photochrom process, which they would eventually register in 1907 under the name Phostint. In addition they would also distributed Swiss made prints for Fussli in America. When the well known Western photographer William Henry Jackson joined the company as a partner, he added his thousands of negatives to Livingstone’s collection of Great Lakes imagery and Husher’s photos of California. All this provided a strong foundation to start publishing postcards. Jackson traveled around the United States taking many additional pictures until 1903 when he took over the management of Detroit’s factory. By 1904 as postcards sales increased to 7 million per year they changed their name to the Detroit Publishing Company. They produced postcards on a great variety of subjects but they are best known for their view-cards. The quality of their cards are considered some of the finest produced in America. They also printed many contract cards whose numbers increased as ordinary sales began to fall. Many of their views found on postcards were also produced as larger sized prints. Detroit went into receivership in 1924 but printed contract cards until 1932. The look of these cards changed over the years as the phostint technique was secretly perfected. All their cards were printed in Detroit except for a rare few from Austria and Switzerland.
The company kept very good records of their printing history and so I know that this particular card was printed in 1902 because it is numbered between 6000 and 6999.