Identification
Three long white days occur with each successive open being within the body
of the previous day and each successive close being higher than the previous
day and near the day’s high.
The Psychology
In a downtrend or during a pullback within an uptrend, the three long
white candles speak for themselves. If volume accompanies the move, the
reliability of the pattern increases significantly.
Here is an example of a bullish Three White Soldiers formation that formed well into CP's uptrend. I personally think it's a little late to chase the stock, so this merely serves as an example of what this pattern looks like.