Tough question. You might try bearing forum.
Where are you reading the part number from?
What manufacturer is the bearing (should be stamped on the bearing)?
Is there an AFBMA number (including suffixes) listed on the motor nameplate? (should start with 60BC03... what comes after that?)
What type of motor?
** If this is simple horizontal motor with no special requirements, I'd think any 6312 2Z/C3 would do. When you replace the bearing, put compatible grease into cavity (half full) as what bearing manufacturer will provide within the new double-shielded beairng. (usually Polyrex EM will be fine... compatible with most)
The bearings belongs to one fan induction squirrel cage motor mounted in one subway. The manufacturer is SKF and no AFBMA code, the letters and numbers are wrotte in the external bearing race way. We are in contact with the manufacturer and for the moment no answer.
GWB is definitely a grease code. Polyrex EM perhaps, but a call to the SKF tech line should resolve that. The /R806 is probably a fill volume or other modifier on the grease.