London Underground X
The London Underground is based on the preamp of the legendary Orange AD200B. It has some similarities to Particle Accelerator, but aside from a different voicing London Underground also gets more drive when the gain is turned up.
A popular request has been a London Underground with a Particle Accelerator tone stack, which gives the bite of London Underground with the richer low end of the Particle Accelerator. This is available at no additional cost, just make a note of “PA tone stack” or something similar in the notes section when ordering.