Small Gauge FIGHTING OPTIONS!
Early war small gauge trains with guns would be so cool. Having a small armored locomotive first week of war would be epic, like an armored train car open top 20mm turret (AA ship turrets) and closed 14.5mm gun sponsons (from the push gun variants with extra ammo). Could be useful for early war and against scout planes.
Mid war modifications for a mini rail cannon (make 250 based again!) being a single barrel 250mm that shoots 40 meters (if they get that close with a small gauge 250 they deserve it, also cool af).
A heavier (higher hp than early war so it doesn't get out scaled as hard into late war) armored train car closed top 40/68 version with 12.7mm sponsons (can be used in AA mode), open top flak platform that opens and closes(deploys) that uses the new aa ammo.
Late war modifications, similar to the A setup, the broadsides 75 and 94.5 small car options have two fire modes, closed top that can only point 30 degrees down a rail direction and can shoot, and when you deploy it into open top, it allows the gun to move 360 but must be stationary. Also makes it vulnerable to being shot out. Would cost steel.
Endwar modifications. Mini nukes! 💥 (Doesn't do nuke things, just cool large explosions) These would be an explosion radius of 10m. The car would be faction locked equipment when built so no capturing. It would need 40 pcons and 5 300mm worth of unstable material. Cooked on a steel Talos/std pad. These don't disable but can die to concentrated rifle fire is a dazzling display of raw explosive power. Think Helms deep. Throw bodies into a wall to keep them occupied while the one guy with a bright sparkler runs into the wall to suicide. Sure the last three guys died to bullet fire, and the last cart exploded to a stray 40mm causing the track to explode violently and needing to be rebuilt. But boy, is this cart going to kill the enemy trench holding the entire front this time! Would be a fun gameplay loop to clear trenches, defenses, push deep into townhalls as infantry and create a natural team building exercise or lose the front mentality!
I think having an alternative to standard tank gameplay is something I yearn for. I love tanks, but boy do I want something that can't be tracked, and is just as great as a support defense option. And this would be a great middle ground between the fast pace of tanks and the slow nature of wheelchair push guns. Cant get tracked but can get turreted. Has less health than a wheelchair, but has armor value.