Update Aug 27,2018: Most of the racks have been partially fixed with two security nuts and two standard nuts, one on each end. A theif needs two different wrenches to deal with this. Check ALL bike racks everywhere for the same problem: if they are bolted down with exposed regular nuts they are vulnerable. Some new bike racks have round baseplates wide enough that U-locks won’t slip past them are these are not vulnerable unless a thief is willing to cart bike and rack away together. The best racks are probably those which are concreted down.
The bicycle racks at Union Station in Washinton DC have become unsafe to lock a bicycle to, as bike thieves have removed many of the nuts holding the U-shaped racks to the concrete. In addition, many of them now have ordinary hex nuts, not the original security nuts holding them down. Anyone with a wrench can remove the hex nuts, and obviously someone is able to remove the security nuts as well. The steel bases on each end of the U sections are small enough to pass through a U-lock.
Finger points to special security nut on base of bike rack, other is unsafe hex nut anyone can remove. Unknown if Union Station is out of security nuts or thieves are installing hex nuts themselves
Once a bike thief removes the nuts, the base of the rack can be passed right through your U-lock and your bike is GONE!
Some of the U-racks have no nuts holding them down at all and are obvious, but others are subtle, with one hex nut on each end. These are easily mistaken for “secure” and obviously bikes are being stolen or nobody would be bothering to remove the nuts.
If you must use these bike racks, first find one with at least one security nut on each end, and nuts on all four studs. Then, remove the bike’s front wheel and lock it alongside the rear wheel, with the lock passing through both wheels and the frame. A thief may still be able to get the rack out of the lock by removing all four nuts, but if he does he still cannot ride the bike and it is very clumsy to carry with both wheels locked to the frame in the rear. He may also find that the space in the lock is now so full of frame and wheels that the base of the rack no longer fits through the lock. If you have a lock small enough that the bases of the racks can’t pass through it at all, use it. Better idea: forget the racks entirely and lock to a signpost until this is fixed.
This sort of thing could happen anywhere this kind of oudoor bike rack is popular, so when using these anywhere, always check that all four nuts are in use and that they are security nuts, or that your lock is small enough that the feet of the rack can’t pass through it.
Note: we don’t need more cops to fix this, we need more mechanics. First put real security nuts back on the studs to discourage casual tampering. Then either weld them to the studs or mushroom over the tops of the studs with a sledgehammer so nobody can remove the nuts with a wrench.