The following website contains useful information about passenger ships:

http://www.geocities.com/Athens/Parthenon/3649/ship-i-k.html#K

The Koln (Koln-2) did begin plying the Bremen-Baltimore route in 1899.
I believe Morton Allen only lists arrivals in New York and
Philadelphia, which is why the Koln would not appear there.

Monica Leonards
Glenside, PA