225T is a thermite welding truck. That is one of the older trucks, there are 4 new Freightliner versions on the property.
270T is a boom truck. It almost never moves ties, that's what a grapple truck is for. There is only a small hook on the end of the boom. It's used to move lengths or rail, Insulated Joints (IJs), small equipment etc, basically anything that needs to be picked up and put down. It doesn't have the ability to move any type of railcar. However it is used to pull a tow behind rail brush on the main line east of KO during leaf season.
This is the new version, we have an older one:
https://www.swingmastercorp.com/product ... railbrush/
Third rail also has these trucks, the three digit number would be followed by an E in this case instead of the T for track.