Ok.... help me out here....

One bridge that is 47 feet long

Two approach spans, each 12 feet long

According to my meager math skills that adds up to 71 feet of span

Across a 74 foot gap....

What am I missing here?

Is our wonderful machine shop working on a new star trek levitation device for the other three feet?

Will the three foot gap be divided into half so each end of bridge will only require the trains to jump a 1 1/2 foot gap?

Oh.... wait.... I figured it out.... if we put a 3/4 foot gap between each end of the bridge and the approach spans.... then.... will the radius of the wheels allow them to bridge (pun intended) the gap?

Might work on the locomotive with the larger wheels but what about the cars....

Oh well, it snowed today and cabin fever is setting in and now my brain hurts....