Even if entertainment-based company Viacom Inc. does sign a deal to anchor Block 37 project, the city of Chicago, Illinois and real estate company Mills Corp., the project's master developer, will have to dig deep to pay for an underground $200-million-plus Chicago Transit Authority express-train station that would whisk travelers to O' Hare International and Midway airports. Given Mills' estimated monthly out-of-pocket expenses in the hundreds of thousands of dollars and the city's past struggles to develop Block 37, a sense of urgency is building. Mills and city officials also have made it clear that Block 37 won't be developed overnight, given softness in the real estate market and the complexity of the 1-million-square-foot project, which would include retail, hotel, residential and office space. Dropping radio and making other space-saving changes means that Viacom now only needs only about 100,000 to 120,000 square feet at Block 37.