The need for buses on the Danbury Branch rail line that serves Wilton should subside in the coming months as the reliability of the rail fleet improves, according to Metro-North.

The rail operator told riders in a leaflet left on train seats this month that a frequent cause of delays has been  locomotive failures.

“To address this issue, Metro-North Railroad has initiated a diesel locomotive overhaul program. The first of these overhauled locomotives is scheduled to be in service before the end of 2018 with others being placed into service over the next few years. These locomotives will bring a much higher degree of reliability to the Danbury Branch and Waterbury Branch Lines,” the rail company said in the leaflet, a copy of which was provided to The Bulletin.

When service is disrupted, particularly on the branch lines, the number of trains is limited, and Metro-North has provided alternate bus service whenever possible.

Unfortunately, the company said, it was unable to do that in a number of instances as partner bus companies were unable to supply buses when requested.

“We realize this can be a significant inconvenience to our customers, so we are redoubling our efforts to ensure buses are available,” Metro-North said.

On-time performance varied from 85% in January to the 90% range between March and May, and back to 86% in June.

Also, there have been 86 Danbury Branch 100% days in 2018; most recently Aug. 25, Aug. 31, Sept. 1, Sept. 2, and Sept. 8.

By national industry standard, a commuter train is considered on time if it arrives at its final destination within five minutes and 59 seconds of its scheduled arrival time.

Generally, the recent trend of late trains on the New Haven Line, including the New Canaan, Danbury, and Waterbury Branch Lines, has primarily been the result of extensive, ongoing upgrades to infrastructure to ensure safe operations and make service more reliable in the future, the company said.

On the New Haven Line, delays have been largely the result of track outages and speed restrictions necessary to accommodate an infrastructure investment program funded by the state of Connecticut. Much of this work will continue into 2019 and beyond.

Projects include the construction of new bridges in Greenwich and Stamford, the continuation of the overhead catenary power replacement program, and the construction of a new railroad interlocking in East Norwalk. To accommodate the work, tracks have been taken out of service. Unfortunately, the company said, with fewer tracks in service, flexibility is reduced if another operational issue should arise.

This track improvement program extends to the Danbury Branch. Projects include resurfacing track, welding joints, tree trimming, Positive Train Control (PTC) installations, grade crossing renewals, and installation of new railroad ties.

The potential for train delays on the branch lines is compounded by late train service on the New Haven Line, the company said.

This summer, two-thirds of all train delays on the branch lines were the result of late connections with New Haven Line trains.

“Work will continue on the branch lines through the fall, and we will make every effort to minimize service impacts,” the company said the leaflet.