If you have summer fruiting raspberries i.e. you are picking the fruit now or have jsut finished picking , the you should cut these fruited canes down to ground level and let the new canes grow - cutting/pulling out any that you don't want. the fruit grows on these new canes. I grow mine straight up - its not really training more a matter of support and tidiness. Two tall poles at each end and in the middle with 3 levels of wire strung along to keep the canes under control!. Works for me.
Autumn fruiting rasps are different, they crop later (autumn!) and all the canes get cut right down in spring (about Feb I believe) and the new canes don't have to be thinned so much.
