Crankshaft Tunnel Bearings
 

Does anyone have information/memories about tunnel type crankshafts and bearings as used on the Maybach and Saurer diesel engines.
I've managed to find some info via the Illustrated Encyclopedia of World Railway Locomotives, and I've got the 'Pitman' Steam to Diesel driver's handbook but I'd be very interested to hear from any members with hands on experience.
Things like reliability in service, hours between overhaul, performance compared to shell bearings etc, or just general observations.

Many thanks in advance.:)