Locotrol

[1][2] Locotrol was developed in the 1960s by an Ohio telephone and electronics manufacturer, North Electric Company.

The electronics were mounted in a separate railcar, but have since been miniaturised into relatively small cabinets with much of the functionality contained in software.

Today numerous railroads use Locotrol, with systems deployed globally numbering in the thousands.

Since 1975, both Queensland Rail and Mount Newman railway in Australia have used the system on coal and iron ore trains, permitting the doubling in the size of trains without exceeding draw-gear strength, through the use of mid-train locomotives.

[8] BNSF and Union Pacific are major North American Locotrol operators.

A mid-train locomotive controlled remotely through Locotrol from the lead locomotive, which means no crew is needed on this locomotive.