As best as I understand US and UK broad Gauge tracks where totally different with the Ohio Broad Gauge at 4' 10" the Erie 6', the Missouri and Texas 5' 6", and the South Carolina Railroad 5' in the UK Isambard Kingdom Brunel’s broad gauge was 7 ft 0¼ and standard gauge at 4 ft 8½ in so in the UK a lot more than 3” difference