Never heard of CAT1B. Maybe this is about
SA CAT 1 which might be available on the runway.
With an
SA (special authorization) CAT 1, you can basically land with a lower
DH and RVR value on a CAT 1 apprch, down to a
DH of 150ft and RVR 1400ft, if you meet the OPS SPEC requirements.
Checked on airnav.com, and no such plates for Reading so far. Still showing the ones that expired at 0900Z this morning. They should update with the new ones any day now.
It is only CATIII approaches that are subdivided into CATIIIa, b or c. CAT I and II approaches don't have that.
[Edited 2015-01-08 06:30:26]
us Air Traffic Controllers have a good record, we haven't left one up there yet !!