Garl was the owner of Latham Railway Services, a Texas-based planning and consulting firm. 

Latham's background includes 10 years with the National Railroad Passenger Corporation (Amtrak) and 5 years at Dallas Area Rapid Transit, where he received the "Golden Star" - DART's highest-level employee award.

He was a native of Dallas and a fifth-generation Texan. He holds an Associate degree from Richland College in Dallas, a B.S. from East Texas State University (today's Texas A&M, Commerce) and several professional certifications.

Garl served as a board member and officer with many professional and advocacy organizations, including the National Association of Railroad Passengers, Southwest Railroad Historical Society and MobilityDallas. He was President of the Texas Association of Railroad Passengers and served a term on the board of Texas Rail Advocates in the early years of the organization.

Latham was a full member of the American Railway Engineering and Maintenance-of-Way Association (AREMA) and an Associate Member of the American Society of Civil Engineers.  He previously made numerous radio, television and personal appearances throughout North America.

Past projects included the design of intermodal freight terminals, evaluation and testing of Maintenance-of-Way construction materials, and a comprehensive study of potential intercity passenger train routes throughout Texas and the southwestern United States.

Among other notable ventures were feasibility and engineering studies for a proposed Dallas, Southeastern and Gulf Railway and the Texas Boxcar Company (TexBox), as well as the design and development of various model and toy trains.

A respected railroad historian, Latham wrote many articles on Post-World War II-era passenger train services, while assisting countless others in their quest for accurate and entertaining information regarding railroading's colourful past. He is considered one of the foremost authorities on classic Santa Fe Railway passenger operations - especially their famed flagship train, the Super Chief. He traveled more than 350,000 miles by train.

Other interests included music, electronics (KE5YMZ) and first-class travel.  Garl and his lovely wife were blessed with two  daughters, and shared their home with a pair of feisty cats, one rather lethargic fish and a hand-carved wooden quail named "Bob."