@David *******
Alongside Ban Khao Din, the Thailand-Cambodia Friendship Bridge at Nong Ian, currently open only to trucks, will be officially designated as the next Thailand-Cambodia border crossing and open to foreigners, probably sometime this year.
Once this happens, it will become by far the most convenient and fastest border crossing between Thailand and Cambodia. Buses will also be using that border too, including Bangkok-Phnom Penh and Bangkok-Siem Reap services.
However, train passengers will continue to use the Aranyaprathet-Poipet border because the train passes through there.