So you mean 3 sessions a day? It can work if the sled sessions are very short and you don't leave them fatigued. BUT from experience very few people can pull it off, most will do too much. Let's face it: if you are asking about training 3x a day, you are likely excessive (like I am) and equate doing more with always being better and people like us will tend to do too much for optimal progress.
Also keep in mind that the sled work is really a recovery tool in that it helps pull nutrients inside the worked muscles, so you want to use a nutrients-rich formula (PLAZMA) prior to every session for it to be effective.