There's a lot of other interesting railway and model railway material in that British web site. One bit of info mentions that Brunel's broad gauge track had a distinctive appearance because the rails were laid on longitudinal stringers with widely spaced crossties. We could use that story to explain why traditional Lionel track has so few ties.
Photo from 1892 shows broad gauge track being converted to standard gauge. It looks like the cross-ties have been cut shorter so one rail can be slid over.