The answer, of course, is money. The state pays about half the bill for the MARC line's operations (the other half is paid through ticket sales), and Maryland's transportation funds have generally been strapped enough for cash to make new services a tall order. However, Gov. Martin O'Malley has made expanded MARC service a priority, so funding for weekend service was included as part of the massive transportation and road construction bill made possible by the legislature's decision to increase the gas tax for the first time in two decades. Expanded MARC train service is a powerful economic development tool that creates new opportunities for residents and visitors in both cities, so it's no wonder business groups and mass transit activists have been advocating such a step for years.