There was previously a feature request for this, but I think it was incorrectly marked as completed.

https://peaksware.uservoice.com/forums/964442-trainingpeaks-virtual-customer-feedback/suggestions/49244876-custom-workout-accessibility-across-multiple-devic

It would be good to be able to store your custom workout files in the cloud (i.e. as an enhancement to TrainingPeaks) so that they are available across all of your devices. The file sizes are only very small so this should be feasible even for very large libraries.

Whilst you can add a workout to TP to have it available in TPV, if you don't have access to the file in the first place because it's on your home PC and you are at the gym, that's no use.