Looking at the photos in "Two Feet to Tidewater" on pages 96 and 97, it appears that the span of the bridge at Carlton Brook is less than the length of the three-door baggage mail car, which I believe was 46 feet. So the span of the actual bridge may be 40 feet, more or less. It also appears that the approach to the bridge, at least on the north side, may have been timber cribbing filled with rock, although what appears to be cribbing may also be ties and other timber unloaded there to aid in the recovery of the wreckage. In any case, it looks as though the north approach is shorter than the south approach. If the bridge's span is 40 feet and the distance between the bridge seats is 70 feet, the approaches must total 30 feet.