On Saturday, March 31, 2018 I created a KML file using Google Earth. I translated it to a GPX file using GPSBable.
I then created a map on ArcGis online for use on my mobile device. The GPX file loaded OK, but any time
I zoomed or dragged the map, Explorer (ArcGis Mobile Explorer for iPhone) crashed. The map I made is public and can be seen here: https://arcg.is/1DyjSK or by searching for "Llano-Brenham-H&TC" -- it's a map of all the railroad lines, spurs and sidings between Llano and Brenham, Texas on the Houston and Texas Central Railroad (H&TC).
The KML files is 259,159 bytes in size and the GPX files is 433,863 bytes.
The GPX file is attached.