UK Controllers/Transformers???

A Question for UK folks running American N Scale.
I have a single track main line predominately modelling passenger working on the Santa-Fe Mountain Division. My layout is powered by a Gaugemaster 100M. I use their HF track cleaner {Wonderful gadget that it is!} and there are 7 Atlas remote turnouts powered by it as well.
My problems have come when I run my Kato Passenger train. This is pulled by a Four Unit Consist of Kato F Units and is made up of a 12 car train of illuminated corrugated side streamline cars.
However as the 100M is only rated at 2.5 Amp this is too greater a load and the cut out operates.
In the States I see from the Adverts in MR that controller/transformers appear made for larger American style consists. Gaugemaster have suggested their 100M-O rated at 5 Amp but as I cannot afford to fit DCC is this my best option or has anyone else any other ideas?

 

We hit the same type of issue in HO over here with Athearn's (they use a somewhat less efficient motor), we still can't run more than two Athearn's together (we have managed more than 6 mixed Atlas & Kato's, driven carefully!!!), but two Athearn's plus dummies are more than enough grunt to move one of our trains so it's not an unworkable situation.

One thought I had, if it's just that one set of loco's that you are having a problem with, could you temporarily (and reversibly) convert one or both B units to dummies? I don't know about in N scale, but in HO you can do that to most diesels by taking out the worm gears and disconnecting one motor wire, those sort of modifications should be reversable if you ever change your mind or want to sell it. I've done this with a couple of Athearn and P2K loco's that just would refuse to run in multiple with what I wanted them too, and it's been fairly sucsessful.