How do I make my F3 A units only run forward.

[Maine2020]

I have two F3 Sante Fe A units powered and I want them to run in the same direction.  How do I turn off the directional control on these Willaims units

[trainyardjp]

If the electronic E-units have a switch, simply set the switch to the 'off' position to electronically 'lock' the locos in the same direction.

If the electronic E-units don't have a switch, the 'default' direction for Williams locomotives is always forward. The default direction cycle should be forward / neutral / reverse etc.

One other method would be to disable the electronic E-Unit, and install an AC rectifier, so your locos will be permanently locked in the desired directions.
Just my opinion.
-JP