OMAHA, Neb. (AP) — Union Pacific says it expects to finish installing and testing a new automatic braking system on the railroad by the end of 2020.

The Omaha, Nebraska, based railroad said it is continuing to install the required positive train control system on 17,000 miles of its track.

The installation should be largely completed this year, but the railroad expects to continue testing and refining the system in next year and in 2020.

Officials with the National Transportation Safety Board have been urging railroads to install such systems for years because they can prevent deadly railroad crashes.

Union Pacific operates 32,400 miles of track in 23 western states.