Jeppesen GPX files contain position, elevation and time but no speed. I used GPS visualizer to convert the GPX format to KMZ (Google Earth). Theoretically speed could be calculated from positions and times, but unfortunately the time stamp does not include seconds. Therefore the calculated speed is zero for a minute, and shows a wrong value when time changes from one minute to the next. Moreover a series of positions with the same time stamp does not make sense for a moving aircraft.
Please add seconds to the time stamp. Or even better, include speed and heading in the GPX files.