Work will expand to include "remaining coastal communities between Oceanside and Old Town in San Diego" as the year progresses.
"NCTD will have as many as three work crews in the right-of-way along the entire length of the work zone with up to eight people in each crew. The crews will be moving non-contiguously, from one area to another as rail segments become available," NCTD said.
NCTD did not indicate whether train schedules would be altered or disrupted in any way, but did caution, "While the work began in January, the onset of warmer weather and open windows may make the work more noticeable to residents along the rail corridor. In addition to the work crews, residents may hear the horns from trains as they enter the immediate work zones.
"Under federal rail regulations, train engineers are required to sound the horns when roadway workers, trespassers, animals or objects are in the rail right-of-way," NCTD said.
The route also is used by Amtrak trains linking San Diego and Los Angeles.