As far as I know the GO and UPX system is the most basic possible.
You tap on. You tap off.
Unfortunately during the recent fare integration between GO+UPX (now identical fare) the fare programming is currently
malfunctioning when you tap-on a GO reader and tap-out a UPX reader, or vice versa. It wasn't designed to do this, now they are fixing that "bug"
Also, another bug...
GO loyalty now counts on UPX. But you must tap on a GO reader to ride UPX, in order to get
unlimited 'free' UPX rides (now allowed) for your Weston corridor station pair after your 40th ride in a month. The UPX Presto (at moment) apparently
does not support GO train loyalty. It does not matter what train you catch (GO or UPX) if you are a Bloor-Weston, Union-Bloor, or Weston-Union commuter, it is now considered identical for loyalty count.
Monopoly board game pun:
Do not pass
GO, do not collect $200, disembark and
walk past the UPX Presto machine, and
tapout on the regular GO reader at Bloor or Weston. At least, it is currently this way for a moment if you wanted to rack up a Loyalty trip count! PROOF:
Metrolinx.com tells you to use regular GO reader for UPX rides for Bloor/Weston commuters to/from Union.
Anecdotally, Metrolinx is working on it all supposedly, so it will eventually not matter which reader you tap in/out of for whichever trip paid you make, and whether or not you transfer. Loyalty will count on either, and you can tap in/tap on either, treating UPX and GO as being identical from a fare perspective and loyalty perspective, on presto reader infotech. Default trips will now work for UPX (yay Bloor and Weston residents) who will no longer need to tapout for either GO or UPX.
Also, I heard they want it so transferring between GO and UPX is becoming modified to become more like transferring between two GO trains -- from the intermediate tapout-tapin perspective.
Fixing the IT issues in two incompatible Presto readers isn't an overnight task...
Both UPX and GO are now identical in Weston Corridor fare treatment now, this is apparent Metrolinx intent, and they are scrambling their IT to fix inconsistencies.