IT HAS BEEN more than a full year since that terrible high-speed crash in Maryland of Amtrak's holiday-packed Colonial passenger train into a string of Conrail freight locomotives -- but the lessons so painfully learned from that tragedy have yet to produce any serious improvements in rail safety. Is everyone content just to read reports, wait for the trial of the Conrail engineer on 16 counts of manslaughter -- and hope this sort of thing never happens again? Or will Congress and every appropriate authority insist on measures and sanctions that could protect the public from another crash such as this one?

Certainly the issues have been set forth for responses. One is drug use, another is safety equipment. On Wednesday the National Transportation Safety Board ended its investigation into the Jan. 4, 1987, crash, which killed 16 and injured 175. The report concluded that the Conrail engineer was impaired by marijuana when his freight train ran through stop signals and a closed switch in front of the Colonial. This finding will be the further subject of a trial of the engineer, but why hasn't there been agreement on some kind of testing -- and more important, on federal power to punish train crew members who violate safety rules?

The report also criticized the Federal Railroad Administration's supervision of Amtrak and Conrail operations in the Northeast corridor, citing the agency for failing to require that locomotives along this stretch be equipped with devices that automatically slow or stop trains that fail to respond properly to signals. Joseph Nall, who supervised the investigation, said the board "would like to see, immediately, every train in the Northeast corridor equipped with automatic train control. We are very concerned with the possibility of another accident like this occurring."

FRA chief John Riley agreed with the need for these controls -- but noted that the safety board itself had rescinded a similar recommendation in 1982. So what about congressional action? Rail safety bills have been passed by the House and Senate, but the compromise necessary for enactment has yet to emerge. Whatever laws are enacted, enforcement, too, should be strengthened.

Enough reporting, finger pointing, explaining, mitigating and litigating: a year has passed, and there are obvious steps to be taken now -- before anything like the wreck of the Colonial is allowed to happen again.