In general, track workouts have a higher neuromuscular component than road cycling on a geared bike. For example, when I do a structured workout at the track, I start out in a warmup gear. I then change to race gears. I race in a 94 or 96. So all the efforts I do including getting on the track and accelerating to speed or any effort or change in speed will require an acceleration in 96 gear inches. Over time, these accelerations are very fatiguing due to stress put on the muscles.
If the workout is a sprint workout including a warmup, jumps and 4x100 meter flying max efforts, that will wreck me. And the fatigue hangs around.
The coach I used last year has a derating scale for his track and trainer workouts. He provides a workout and depending on whether one does it on the road, track or trainer, the durations are modified to take into account the effects of the track and trainer versus the road.