NEWARK, N.J. (CBSNewYork/AP)New Jersey Transit says it will temporarily shut down and limit some train service as it works to install a federally mandated safety system by a Dec. 31 deadline.

The service changes will go into effect on June 4 and last through early next year.

Last week the Federal Railroad Administration sent a letter expressing concern that NJ Transit, the nation’s third-largest transit system, would miss the deadline to install the emergency braking system, called positive train control.

Positive train control, or PTC, is an advanced computer system designed to override the engineer and automatically stop a train before certain accidents occur. If a train operator is moving too fast, PTC will apply brakes.

Through the end of 2017, NJ Transit reported it had only 35 of 440 locomotives equipped with the system, and hadn’t finished installation on any track segments.

Last month, NJ Transit Executive Director Kevin Corbett said an overnight test of the system on tracks in Morris County had been successful.

Rail expert Robert “Buzz” Paaswell told CBS2’s Alice Gainer it isn’t just a hardware installation — there’s also employee training that has to be done.

“The installation and testing could take up to a month with all the testing and going back-and-forth,” he said.

Paaswell said although NJ TRANSIT is already very crowded, he doesn’t believe there will be too much of a noticeable disruption to service.

“But you’ll realize in the long run this is going to prevent accidents, so it’s worthwhile, he said.

Rockland County Executive Ed Day, however, called the changes “an utter outrage.”

“Rockland is already the most underserved county in the region and canceling two of the four express trains our commuters have is just adding insult to injury. We were already in the process of planning a meeting with NJT to address poor quality of service on the Pascack Valley Line and will add this latest slap in the face to our list of concerns,” he said in a statement. “It’s extremely unfair to our commuters that NJT’s lack of planning on their PTC (Positive Train Control) Project now constitutes an emergency for our riders.”

Service changes announced by NJ Transit are listed below and are available in a printable format online.

NORTHEAST CORRIDOR (NEC)

Three trains have been temporarily discontinued.

INBOUND SERVICE (temporarily discontinued)

Train 5822, the 7:05 a.m. departure from New Brunswick to Newark Penn Station
* Earlier train departs at 6:59 a.m. (limited capacity)
* Later train departs at 7:10 a.m.

OUTBOUND SERVICE (temporarily discontinued)

Train 3811, the 4:51 a.m. departure from Penn Station New York to Trenton Transit Center
* Earlier train departs at 4:17 a.m.
* Later train departs at 5:07 a.m.

Train 5869, the 6:03 p.m. departure from Newark Penn Station to Trenton Transit Center
* Earlier train departs at 5:56 p.m. (limited capacity)
* Later train departs at 6:11 p.m.

NORTH JERSEY COAST LINE (NJCL)

INBOUND SERVICE (temporarily discontinued)

Customers may take alternate service to Secaucus and transfer for service to Hoboken at no extra charge.

Train 2300, the 4:49 a.m. departure from Bay Head to Hoboken

* There is no earlier train option from Bay Head. The earlier inbound train departs from * Long Branch at 4:58 a.m. (Train 2300 previously departed Long Branch at 5:27 a.m.)
* Later train departs Bay Head at 4:57 a.m. and Long Branch at 5:35 a.m.

Train 2602, the 6:05 a.m. departure from Long Branch to Hoboken
* Earlier train departs at 6:01 a.m.
* Later train departs at 6:19 a.m.

Train 2312, the 2:05 p.m. departure from Bay Head to Hoboken
* Earlier train departs at 1:10 p.m.
* Later train departs at 3:05 p.m.

Train 3274, the 6:55 p.m. departure from Long Branch to New York
* Earlier train departs at 6:33 p.m.
* Later train departs at 7:20 p.m.

OUTBOUND SERVICE (temporarily discontinued)

Customers may take alternate service to Secaucus and transfer for service to Long Branch/Bay Head at no extra charge.

Train 2303, the 2:12 p.m. departure from Hoboken to Bay Head
* Earlier train departs at 2:02 p.m. from Newark Penn Station (Train 2303 previously departed Newark at 2:36 p.m.)
* Later train departs at 3:05 p.m. from Newark Penn Station

Train 2607, the 4:55 p.m. departure from Hoboken to Long Branch
* Earlier train departs at 4:54 p.m. from Newark Penn Station (Train 2607 previously departed Newark at 5:18 p.m.)
* Later train departs at 5:25 p.m. from Newark Penn Station

Train 2313, the 6:21 p.m. departure from Hoboken to Bay Head
* Earlier train departs at 6:22 p.m. from Newark Penn Station (Train 2313 previously departed Newark at 6:40 p.m.)
* Later train departs at 6:47 p.m. from Newark Penn Station

RESTORED SERVICE & OTHER ADJUSTMENTS

The following trains will be restored to/from Penn Station New York and will no longer operate to/from Hoboken. These trains were diverted to Hoboken in January as part of Amtrak’s ongoing track improvement project at Penn Station.

Train 3318 will depart Bay Head at 5:40 a.m. and Long Branch at 6:19 a.m. and travel to Newark/New York
* This train will make all station stops to Aberdeen-Matawan and then express to Newark, arriving in Newark at 7:19 a.m. and in New York at 7:42 a.m.

Train 3269 will depart New York at 5:45 p.m. and Newark at 6:04 p.m. and travel to Long Branch
* This train will express to Rahway and then make all station stops to Long Branch, arriving in Long Branch at 7:24 p.m.

The following train has been renumbered and station stops and departure times have been adjusted.

Train 3316 (current 6:11 a.m. departure from Long Branch) will be renumbered as Train 3216 and will now depart from Long Branch at 6:01 a.m. with service to Newark/New York
* This train will make all station stops from Long Branch to South Amboy and then stop at Woodbridge and Avenel before expressing to Newark, arriving in Newark at 7:08 a.m. and in New York at 7:30 a.m.
* This train will no longer serve Bay Head through Elberon stations

MORRIS & ESSEX LINES (M&E)

INBOUND SERVICE (change in origin stations)

Train 608, the 5:45 a.m. departure from Dover to Hoboken, will now originate in Summit (service has been eliminated from Dover to Chatham)
* Earlier train departs Dover at 5:33 a.m. (requires transfer at Newark Broad Street Station for service to Hoboken)
* Later train departs Dover at 5:54 a.m. (requires transfer at Newark Broad Street Station for service to Hoboken)

Train 626, the 8:28 a.m. departure from Dover to Hoboken, will now originate in Morristown (service has been eliminated from Dover to Morris Plains)
* Earlier train departs Dover at 8:08 a.m. (requires transfer at Summit for service to Hoboken)
* Later train departs Dover at 9:06 a.m. (requires transfer at Newark Broad Street Station for service to Hoboken)

OUTBOUND SERVICE (temporarily discontinued)

Train 609, the 6:42 a.m. departure from Hoboken to Dover
* Earlier train departs Hoboken at 6:15 a.m.
* Later train departs Hoboken at 6:55 a.m. (requires transfer at Summit for service to Dover)

Train 645, the 5:08 p.m. departure from Hoboken to Dover
* Earlier train departs Hoboken at 4:42 p.m.
* Later train departs Hoboken at 5:12 p.m. (requires transfer at Newark Broad Street Station for service to Dover)

PASCACK VALLEY LINE (PVL)

Two trains have been temporarily discontinued and service on other trains has been adjusted. These trains are listed along with some travel options to help you plan your trip. Other service changes are available in the new timetable.

INBOUND SERVICE (temporarily discontinued)

Train 1618, the 7:59 a.m. departure from Spring Valley to Hoboken Terminal (Metro-North express)
* Earlier train departs Spring Valley at 7:37 a.m.
* Train 1620 is adjusted five minutes earlier to depart Spring Valley four minutes later than the discontinued Train 1618 (arrives in Hoboken 13 minutes later than the current Train 1618)

OUTBOUND SERVICE (temporarily discontinued)

Train 1639, the 7:20 p.m. departure from Hoboken Terminal to Spring Valley (Metro-North express, Monday through Thursday)
* Earlier train departs Hoboken at 6:48 p.m.
* Later train departs Hoboken at 7:29 p.m.

Train 9653 will no longer operate on Friday afternoons except before major holidays (departs Hoboken at 2:58 p.m.)
* Only days of service: July 3, August 31, November 21 and December 21

Note: Train 1633, the 5:58 p.m. departure from Hoboken, will not operate on July 3, August 31, November 21 or December 21 to provide equipment for this early getaway service

(© Copyright 2018 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)