Congressional hearings about Amtrak dumping human waste along rights-of-way have been tentatively scheduled for Sept. 20.

The hearings were originally planned to be held in Utah but have been scheduled in Washington by the Government Activities and Transportation Subcommittee because of a tight congressional schedule, according Ken Salaets, an aide to Rep. Howard Nielson, R-Utah. Nielson is a minority member on the subcommittee.Nielson hopes the hearing will be a catalyst in requiring Amtrak to retrofit cars so they will dump into municipal sewer systems along the routes rather than spraying the waste from the train. Amtrak uses the spray system on trains routed west of Chicago.

Salaets said that Amtrak has recently revised cost estimates of the plan from $100 million to $34 million. That cost may make an upgrade program easier for Congress to swallow in appropriations over the next several years.

Last month Amtrak agreed to meet several of Nielson's demands to stop dumping the raw sewage including locking toilets of high-level cars while stopped in stations. Amtrak also agreed to raise the speed at which the waste is automatically released from cars.