Three hard-hatted technicians at the Connecticut Rail Maintenance Facility in Stamford worked to install a new air compressor underneath an M-2 rail car Monday morning, just one of more than 19 cars at the hangar-like structure waiting for repairs due to the recent streak of brutal winter weather.

The air compressor was damaged by moisture from snow along the tracks ingested into brake lines, said John Hogan, assistant mechanical officer for Metro-North Railroad's New Haven Line.

Although outfitted with an event-reporting system meant to help identify why a car has faltered, additional problems are not readily apparent and extend the time it takes mechanics and engineers to fix worn-down M-2 cars, all of which are 33 to 40 years old, Hogan said.

"It's usually more than one problem," he said. "Once we repair a problem, we might find another while we're testing that it works."

Outside the facility, which can house eight cars at a time, mechanics in orange reflector vests tried to get started on repairs for more recently sidelined cars waiting to enter the shop.

"We do repairs outdoors whenever we can," John Kulka, the New Haven Line's assistant director of yard operations.

And another winter storm is buffeting the region through Wednesday evening, with predicted accumulations of 5 to 9 inches of snow and ice.

Since a major storm the day after Christmas, car mechanics at both the Stamford maintenance facility and at the New Haven rail yard have been working nonstop to repair weather-related damage to the New Haven Line's electric rail fleet, Hogan said.

In recent weeks, customers have been told to expect crowded trains and possible delays because of persistent car shortages.

"We're concerned about this storm because we're working very hard to keep the fleet going," Hogan said. "Things will be better when we get the new cars."

Metro-North President Howard Permut said he is proud of the long hours maintenance workers have committed to maintain New Haven Line service.

"The Metro-North forces from the senior vice president on down through all the people down in the shops have worked unrelentingly for five weeks, and that includes weekends and holidays, and all of that continues so we can continue to run some level of service on the New Haven Line," Permut said. "But we're up against unprecedented winter weather combined with a fleet in desperate condition. We have a huge storm coming and we have to assume tomorrow will be as difficult as today."

During and after storms in January, the railroad has canceled and combined trains, and operated fewer cars than normally required, resulting in crowded conditions aboard trains, spokeswoman Marjorie Anders said.

With 139 cars out of service Monday morning, Metro-North was more than 80 short of the 262 available cars it needs to run full weekday service, Anders said.

On Monday, the railroad used seven diesel locomotives pulling five coaches each to cover some rush-hour runs and help lessen the effect of the electric car shortage on the New Haven Line, Anders said.

Last Friday, 181 of the New Haven Line's M-2, M-4, and M-6 rail cars were out of service, more than half its 320 car fleet, Hogan said. By Monday at 6 a.m., repair crews had cut that to 139 cars.

"This winter has been relentless," Hogan said. "I can't remember a winter when we had so many storms in a row without a chance to recover. You usually get some increase in temperature and the snow will melt, which gives you some time to do repairs and get back to square one."

The railroad operated a Sunday schedule on Saturday, running 29 fewer trains, allowing trackside crews to catch up on maintenance such as digging out frozen railway switches, clearing snow from pantographs on top of cars and clean up railyards.

Eddie Usarzewicz, a foreman from Shelton, said he planned to stay at the facility overnight Monday and Tuesday to avoid difficulty commuting from home, a continuation of the growing number of nights he has slept on a futon at work to avert long delays getting to work.

Usarzewicz, a 25-year veteran of the railroad, said his 10-year-old daughter, Katie, has begun to complain about his extended absences from home over the past month.

"When there is a storm, it is often difficult to get here on time from Shelton," Usarzewicz said. "I'm usually pretty knocked out by the time I'm done working, and just grab something to eat before going to sleep."

One of the most common equipment setbacks is the breakdown of the traction motors that drive the wheel assemblies of the electric cars, caused when snow is sucked in by vent intakes that draw air to cool the engines, Hogan said.

Changing out the vulnerable motors can take up to six hours, and Metro-North has three private firms that rebuild and perform non-routine maintenance on the motors, Hogan said.

"We can do some of the routine maintenance, but mostly it is changing the motors out in the shop," Hogan said.

Even with diesel trains being used to fill slots, Anders said some delays remain inevitable, including those cause by diesels, which accelerate and decelerate more slowly than electric trains.

"Diesels are designed to travel over greater distances, and when you throw a sluggish but reliable diesel onto an electric schedule, it is going to fall behind and cause delays," Anders said. "That is true even if nothing breaks down."

The equipment difficulties underline the importance of getting the New Haven Line's fleet of new M-8 cars, which were expected to reach service in late 2009, through mechanical and mileage tests so they can begin to replace the M-2 cars as soon as possible, Anders said.

Once approved, Metro-North hopes to put up to 12 M-8 cars a month into service, Anders said.

In January, Metro-North got approval for a $12.5 million, seven-month contract extension for a consultant to assist the manufacturer Kawasaki Rail Corp. and Metro-North complete testing of the M-8 rail cars and resolve engineering problems which have delayed their debut.

"We need all of the M-8's including the ones being considered by the state Bond Commission in Connecticut," Anders said. "We believe it is going to be a very good car and there is nothing wrong with it. The testing takes time."