In practice, Class 74 was a rare visitor to Weymouth (because failures on diesel were common and a stranded train, irate passengers and blocked line are highly undesirable) and was usually replaced at Bournemouth by the redoubtable Class 33 for the final leg of the journey. This was almost directly attributable to their problems when running on diesel power and totally negated their "raison d'être". Quite simply; they were not trusted and as a result, they failed to deliver the expected advantages of a higher power (than Class 73) electro-diesel. Services to Southampton Ocean terminal did use them frequently over non-electrified lines, but this required only a few miles of diesel haulage rather than 60+ on the trip to Weymouth and back. Also, following the closure of Southampton Terminus station, the section of non-electrified track served Ocean Terminal exclusively - a failure here would not inconvenience other services - the same was not true West of Bournemouth. The steep ascent from Weymouth would also have taxed their diesel output to the utmost, as the 'Channel Islands Boat Train' usually loaded to 11 cars.