The North County Transit District on Monday advised passengers to avoid boarding a short Coaster train they might see approaching stations, because it's being used for testing.
The test train has a locomotive and a pair of passenger cars, and mostly operates at night. Normal Coaster trains have five passenger cars.
NCTD officials said they want to get the word out to passengers to reduce confusion.
"We have had instances of people trying to get on this test train when we ran it during the day,'' said Eric Roe, NCTD deputy chief of rail operations. "Future testing will mostly be at night, but we want customers to know what it is in case they see it again at a station."
NCTD is in the process of implementing Positive Train Control, which will enhance the safety of train operations on the coastal rail corridor. PTC helps to prevent accidents from human error and can stop a train when a potential hazard is identified, if an engineer fails to do so.
According to the American Association of Railroads, PTC is designed to prevent train-versus-train collisions, derailments caused by excessive speed, unauthorized incursions by trains onto sections of track where maintenance activities are taking place, and movement of a train through a track switch left in an incorrect position.
Some types of operator error and vehicles crossing in front of trains would not be covered by the system, according to the trade group.
PTC consists of an onboard monitoring system that can track a train's position and speed, and activates braking as necessary to enforce speed restrictions and unauthorized train movement into new sections of track; a wayside system that watches over railroad track signals, switches and track circuits to communicate authorization for movement to the locomotive; and a hub that stores data on the rail network and trains in operation, and transmits authorization for individual trains to move into new segments of track.
The current testing of PTC on this train is part of the process of ensuring proper functionality of the technology and is a necessary step for full implementation, according to the NCTD. District officials began working on PTC in 2008, and hope to have the system ready in two years.