It’s the diagram for their 4-across variant of their ‘Lightning’ train…
…the one intended for their SRII competitor, the Double Heart.
As for “Food for thought”, I believe he’s suggesting the use of the 4-across variant over the 2-across one that was unveiled alongside the first known accelerator conversion (the train posted by Rivals, black & pink on yellow track) to boost TTD’s capacity.
If that was the intention, then entertaining the idea (and disregarding that it’s very unlikely for the track gauges to match), having 120+mph in your face with no zero car sounds like torture for the front row.