When Metro officials were getting ready to design the Washington subway several years ago, many of them visited other cities around the world in search of ideas.

They ignored one of the best ideas, as thousands of commuters will discover on Monday when Metro stops running dozens of its bus lines all the way downtown and starts transferring passengers to trains at several outlying stations.

The idea Metro ignored is well-designed, weather-protected stations where passengers can change vehicles speedily and conveniently.

By the standards of Toronto, location of the first all-new subway system built in North America after World War II, Metro's arrangements in Washington are primitive. No other word will do.

Metro officials will tell you that the stations where transferring will begin on Monday - chiefly Rosslyn, Stadium-Armory and Potomac Avenue SE - are only temporary, and that most bus-rail interchanges in the future will take place at stations one deeper in the suburbs. But even the designs of those stations will be inferior.

On our Metro, passengers who go from the comfortable subway stations to catch buses will be subject to the vagaries of Washington weather - the sweltering heat of summer, the biting cold of winter, and the positive discomforts of little or no shelter from rain and snow.

These are the very things that discourage many people from going down to the corner and waiting for a bus today. They are the things that may discourage people from using Metro's much-touted coordinated rail and bus system.

The Rosslyn bus terminal, for instance, is nothing more than several unprotected "bus stop" signs strung out along a block of North Moore Street, with a small shelter perched inconveniently at one end of the block. The Pentagon terminal, where Shirley Highway bus riders will start transferring overhead, but lacks lateral shelter from the north wind that in winter drivers across the nearby Potomac.

As cities such as Toronto and Hamburg, Germany, have long demonstrated, and as a new project in Jersey City now demonstrates, this really wasn't necessary. These cities have proved it is possible to design transfer terminals that are comfortable and convenient, and offer efficient operation to the transit authority.

I first visited Toronto's subway system in 1959. What impressed me perhaps the most was the way the Eglinton bus-rail transfer terminal functioned.

Eglinton was at the outer end of Toronto's first 4 1/2-mile subway line. You could compare the neighborhood to Rosslyn or downtown Silver Spring. Numerous bus routes converged upon the rail terminal, serving as feeders.

It was possible to get off a train in the station's basement, ride an escalator to a broad corridor-like concourse (enlivened by newsstand kiosks and numerous small shops), then walk up one of a number of short stairways to a sheltered platform at the side of your bus. Lighted signs informed you when you bus was ready to load.

When destined for downtown, a passenger would have paid the full fare on the feeder bus and transferred to the train without the bother of passing through another turnstile. How much more efficient than Metro's electronic farecard system.

Toronto's system works because, except for a few long suburban buslines, there is a single fare throughout the entire transit system.

With Toronto's subway system expanded (26 miles on two routes now operating, 10 miles more being built), Eglinton station has been largely supplanted. Three newer terminals of similar functional design now handle 250,000 passengers during each rush hour. That's about equal to the total number of people who ride on Washington's bus system each rush hour.

Many of the Toronto features are incorporated in a 2-year-old terminal I visited recently in Jersey City, the Journal Square transportation center.

Journal Square is operated by the PATH transit system (the initials stand for Port Authority Trans-Hudson), which interconnects New York City, Jersey City, Hoboken and Newark.

Journal Square is at the center of Jersey City, a drab area that has been in severe decline for years.

PATH officials, led by Louis J. Giambaccini, the system's dedicated and innovative general manager, decided that a new subway station could be the core of a multipurpose facility that could help pull the neighborhood up by its bootstraps.

The result is a facility that includes shops, banks, restaurants, a 617-space parking garage, a fully covered bus terminal with access to adjacent streets, a rail transit station and a modern, 10-story tower of textured concrete that houses PATH administrative offices.

An estimated 74,000 transit passengers use the center each weekday. Of these, 34,000 are PATH rail passengers. About 14,000 persons transfer between trains and buses. The process is almost, but not quite, as simple as the Toronto operation; the New Jersey rail and bus systems are owned separately, and each charges its own fares.

A facility as ambitious as Journal Square is, of course, costly - $87 million, of which $39 million came from the U.S. Department of Transportation, with expenditures limited strictly to transportation facilities. An adaptation of the idea in Washington need not be so ambitious.

What Washington passengers need and deserve is a comfortable, convenient way to transfer between vehicles. There is hope that we may get it as an afterthought - a result, ironically, of Metro's misfortunes.

Roy T. Dodge, Metro's assistant general manager for design and construction, told me recently that Washington may adapt the Toronto and Jersey City approach if a current study (which results from Metro's financial plight) leads to truncating some of the rail lines.

Truncation would result in more bus lines being routed to subway stations closer to downtown Washington, created more congestion and bringing a need for better-designed terminal facilities.

Metro could use such stations, whether the system is truncated or all of the planned 100 miles are built.