i think he / she means train, as in perpetual, a style of growing where you take clones from a mother plant, and either flower the mother and root the clones, finish vegging clones and, either wait for the mother to finish flowering, then flower the clones, or depending on how much room one has, throw the rooted clones directly into flower after taking another set of clones from the clones, and flowering the first set of clones as the second set start to root..
this way you can time how often you have a plant(s) that are ready to harvest, and will always have a constant supply of bud on hand.. you could potentially be harvesting a new plant say once a week, for ever and ever, ad infinity..