First we need to define what we mean by a solo breakaway on the bike. For simplicity I have defined it as an athlete arriving into the second transition at least 10 seconds ahead of the second athlete. Of course this analysis won't tell us how that breakaway occurred, i.e. was it a solo 40km ride or a last-lap breakaway but for the purposes of this analysis it will provide a starting point for further analysis through watching race replays on triathlonlive.tv to gain the required context.
The results of the script show that a successful (as defined above) solo breakaway has only occurred 7 times in WTS history. Here is the full list including event name, athlete name the lead they had off the bike in seconds and their eventual finishing position.
Of the 7 times that a successful solo breakaway has occurred it resulted in a race win on 4 of those occasions. Notably the unique 2013 Kitzbuehel race which is included in both the Elite Men and Elite Women's variants featured a mountain climb which caused large separations between all the athletes.
Through a simple variation of the script it would be possible to determine the occurrence and resulting success of larger group sizes.