Installation:
1. Dump the "metrolinx" folder into "mods\update\x64\dlcpacks" folder using OpenIV
2. Dump "trains.xml" into "mods\update\update.rpf\common\data\levels\gta5" using OpenIV. Make sure to backup the original!
3. Add the following entry to "mods\update\update.rpf\common\data\dlclist.xml"

<Item>dlcpacks:/metrolinx/</Item>

4. In GTA V wait for the train to arrive along the LST stations.