A better type of track bumper might have reduced damage and injuries in the fatal Sept. 29 crash at NJ Transit's Hoboken terminal, according to reporting by David Porter for the Associated Press, and published in the Star-Ledger (Dec. 23). The most modern type of bumper is equipped with hydraulic shock absorbers and sled-like friction shoes, which gradually absorb the energy from a train that collides with the bumper.  No bumper is designed to safely stop a train moving as fast as the 21 mph the inbound train was reported moving on Sept. 29, but a better bumper might well have reduced the damage. Just one track, Track 15, at Hoboken has the new-style bumper; the rest, including where the crash occurred, have rigid concrete-and-steel bumpers, in service since the terminal opened in 1907.  In contrast, NJT's Atlantic City terminal, built 25 years ago, has modern bumpers.  But there's a downside to installing the improved bumpers: in order to slow  a train gradually, they take up track space, reducing the length of trains a platform can accommodate. NJT Executive Director Steve Santoro says NJT would  be forced to run trains "at least" one car shorter, and that new bumpers would "exacerbate an issue that already exists in terms of track length." "We would like every platform to be a 10-car platform, but can't do that." Santoro said that train-length constraints are a physical problem that NJT has to deal with in designing its operations.  Safer bumpers would make those constraints a bigger problem.