The plan was ordered by Congress because of concern that people who ride buses, trains and subways were taking a back seat to airline passengers when it came to security.

In a Sept. 15 letter to Homeland Security Secretary Michael Chertoff, Collins and Lieberman said the people most affected by the plan ought to be able to read it.

"Key partners in transportation security, namely state, local and tribal governments and system owners and operators, are unable to access the document outlining their responsibilities and roles," they wrote.

TSA chief Kip Hawley said Wednesday that the classified version would be shared with people who own and operate transportation systems and that an unclassified version would be made available.