It appears that Loco2 isn't showing the fastest journey for all search queries.
Looking at Anniesland to Taunton departing after 14:30, Loco2 is only showing one available itinerary that departs Anniesland at 14:32 and doesn't get to Taunton until 00:14. Comparing this with Trainsplit and other sites, later journey times are given such as leaving an hour later at 15:32 and getting to Taunton two hours earlier at 22:14 (with only one extra change). The attached photo shows a comparison between Trainsplit and loco2 for the same journey.
Looking at Anniesland to Taunton departing after 14:30, Loco2 is only showing one available itinerary that departs Anniesland at 14:32 and doesn't get to Taunton until 00:14. Comparing this with Trainsplit and other sites, later journey times are given such as leaving an hour later at 15:32 and getting to Taunton two hours earlier at 22:14 (with only one extra change). The attached photo shows a comparison between Trainsplit and loco2 for the same journey.
