The railroad has been a force in American urbanism since the Iron Horse first pushed its way across the Western prairies and mountain ranges. Many Western towns, including Laramie and Cheyenne in Wyoming, were founded by the Union Pacific Railroad during the late 1860s on its drive to complete the Transcontinental Railroad. In other cases, small towns like Omaha, Nebraska, became big cities almost overnight, when thousands of men who worked for the railroad poured into town, followed by the people who made their living (honorably or otherwise) by inducing the railroad men to part with their money.

In present-day California, rail continues to be an urbanizing force. The difference, of course, is that we are building new commuter-rail systems in already developed areas, rather than laying track across miles of wilderness. Perhaps it seems overblown to compare the projects being built in anticipation of the latest expansion of BART to the railroad towns. It is true that so-called "transit-oriented developments" are less spectacular than the sudden growth of railroad towns in the 19th Century, with their tent cities, gamblers, make-shift banks and brothels. In the Bay Area of the early 21st Century, however, the rapid transit system is stimulating new investment in neglected or unglamorous places. And, what is new, the investment is now happening even before the train comes to town.

One recent beneficiary of BART-inspired investment is the city of San Bruno, a bedroom community of 42,000 people in San Mateo County just north of San Francisco International Airport. BART plans to complete a new station within a year just south of Interstate 380 and El Camino Real on the site of the Tanforan Park Shopping Center. The stop for BART, which serves San Francisco and the East Bay, will be within walking distance of an existing station for Caltrain station, which serves the Peninsula and South Bay. For years, the immediate area has been in something like suspended animation; much of the area has been occupied by the Navy's Western Division Naval Facilities Engineering Command (EFA West) which consists of little more than wooden barracks rehabbed as office buildings. A 27-acre Marine Corps Reserve Training Center lies directly north, and is not part of the plan. In 1997, after the Navy decided to close EFA West, the city drafted specific plan calling for a mixed-use district on the 20-acre site. Last spring, the U.S. General Services Administration auctioned off the property for about $20 million to a partnership of The Martin Group and REGIS Homes of Northern California, both of San Francisco.

The resulting project is The Crossing (named for the meeting of the freeway and El Camino Real), a $200 million master plan for 300,000 square feet of office space, a 500-room hotel, 400 dwelling units (of which nearly half are assisted-living units for seniors), and a two-acre park. Twenty acres of land is a big opportunity in San Mateo County, and it is not surprising that two well-heeled developers pounced on the property. The urban design of the former naval site is awkward, however. The site is hemmed in by the freeway to the south, and on the east by the somewhat unsightly strip condition of El Camino Real � a ragtag collection of spa dealers, automotive shops and the like. South of El Camino Real is the enormous asphalt parking lot of the Tanforan mall, a condition which discourages people from walking in the area. To the north is a large brick-and-concrete Marine Corps building.

For better or for worse, The Crossing needs to be an inward-looking, self-contained area. The intent of the developers is to make The Crossing echo the urban design of the Bay Area, according to Martin Group partner David Cropper: streetside parking (but few surface parking lots), wide sidewalks and a continuous street-wall of buildings. In addition, the developers are providing three types of housing: walk-up or "stoop-style" townhouses, loft units above retail, and assisted-living units. In short, the developers want something akin to a miniature San Francisco or Oakland.

The resulting plan by the San Francisco office of St. Louis-based Hellmuth, Obata + Kassabaum (HOK) Inc. reflects the constraints of both the manmade and natural world. To the east, the developers and architects have created a large, formalized public plaza or square; the open space accommodates two, parallel, 40-foot water easements. A pair of identical office buildings serve as bookends for the park. The office buildings look pleasantly symmetrical in plan but may seem oppressively similar when built. In addition, a number of mature pine trees exist on the site, which the architects were careful to preserve by aligning an "esplanade" in a north-south direction down the center of the plan. North of the esplanade is a block of row housing, with its own interior courtyard. Designed with walk-up stairs, the row housing strives to be classic, urban stoop housing. Opposite the row housing is a neighborhood-serving retail strip, which helps hide a multi-story parking structure for the seven-story hotel to the east. If the rest of the plan is turning its back to the freeway, the hotel is an unabashed freeway building. The loft units are located in the commercial building fronting on El Camino Real, while the senior units are off by themselves, just west of the Marine Corps property.

In all, the plan is impressive evidence of the high degree to which mainstream developers have embraced urbanity and genuine mixed-use � undoubtedly because these are elements that are easily marketable to Bay Area professionals. If the plan is admirable for envisioning a "full service" community with urbane values, it is also a little frustrating because the site is so small and the project does not link to the rest of town. Unlike the open spaces traversed by 19th Century locomotives, the urban spaces of the present-day Bay Area are constrained by major roadways and other conditions that can get in the way of creating a larger, pedestrian-oriented city.

The most positive thing to say is that this project is energetic, introduces mixed-use planning notions to the area, and it wants to expand. Happily, the possibility of future growth lies to the north, where the Marine Corps facility will someday be demolished and replaced with new development. The Crossing will have its fullest bloom when new investment � with similar design values, I hope � arrives and enlarges the pedestrian realm of San Bruno.