The Detroit Zoo trains made by Chrysler, one-third regular size, nearly 27 feet long

Built in 1931, the miniature railroad was credited with helping the Detroit Zoological Park survive hard times during the Great Depression. Starting out at a nickel a ride, train fares provided the zoo with dependable revenue. The replica steam locomotives and passenger cars became obsolete in 1948.

The next year, in 1949, the founder of the Chrysler Corporation, Walter P. Chrysler, offered to develop a completely new design and power plant for the the Detroit Zoological Park . The result is a trim eight-ton streamliner train engine: The Walter P. Chrysler.

The job was assigned to the Engineering Division and all the departments—Art, Development and Road Test—helped out. The power plant is a six- cylinder automobile engine with fluid drive and hydraulic transmission. It can make about 25 mph and has a standard Chrysler cooling system.

Chrysler designed, built and donated two more railroad engines in 1950 and 1951. The zoo’s new trains were modeled after the fast, aerodynamic Streamliners of that era.

After serving millions more riders, the trains were idled again in 1980 for repairs. A fund drive raised $300,000, including donations from children’s allowances and proceeds from a zoo garage sale. In 1984, the trains returned to service.

above the 1949, 50, and 51 from right to left

the Scripps, Reuther and Walter P. Chrysler. These trains – which the Detroit Zoo mechanics affectionately refer to as Scrippy, Ruthy and Wally – are still in use today, with rides offered daily from May to October

http://ibls.org/mediawiki/index.php?title=Chrysler_Builds_A_Locomotive
http://www.railroadmichigan.com/miniaturenarrowgauge.html
http://www.uaw-chrysler.com/images/news/zootrain.html

Tim Wade, the son of an aviation mechanic, has been able to improve the efficiency of the railroad system since being hired as to the zoo's maintenance department in 2014. Wade grew up racing cars, and has changed the entire way that the trains are maintained and repaired.

https://detroitzooblog.org/2016/07/13/on-the-right-track-detroit-zoo-trains-ride-high/