It's not really a bad suggestion, but it would be useless to the vast majority of torn. From my experience directors usually do only one or two trains per employee per day so instaclicking twice isn't really that big of a deal and those who dump all the trains onto one employee also don't really have a need to count them.
On one hand it would save a few seconds a day and let the mouse live a little longer, on the other hand from my experience in buying trains I usually checked if I was trained the right amount by dumping the logs into excel and searching to see the amount of logs received. Wouldn't be that much of a deal when company is always at the same rating, but it's not and this would make it needlessly more annoying just for a sake of saving few clicks.