Trinity Metro allows up to 20-hour free parking at the TEXRail stations in North Richland Hills, so if you work a night shift or a double shift, or plan a day trip, you will be able to park in the TEXRail station lot. If you are planning to be out of town for two or more days, you should get a ride to the station and use the easy drop-off lanes.
The issue regarding long term parking is that if the rail station lots fill up with travelers who are gone days or weeks at a time, then there will not be enough space for daily commuters to park. Options for long term parking are being explored and could be added at a later date.
Visit https://ridetrinitymetro.org/texrail/about-texrail/faqs/ for more information.