I've been looking at a railway bridge here in northwest Thailand which apparently has three shell holes from WW2. I've completed a first draft for a webpage on the subject here: San Khayom Bridge. But the presentation is weak because I can't really say with any assurance what produced the damage. Since Thailand was a member of the Axis during WWII, I think I can reasonably assume that the two smaller holes probably came from an Allied aircraft strafing Thai railway rolling stock as it entered the bridge --- that is, if the projectiles, that hit the bridge, were 50BMG which "spread" on hitting structural steel, growing from .50 caliber to 7/8 and 1 inch. A possible source of the larger hole with diameter over 2 inches, though, is less clear. So I'm looking for assistance / direction in interpreting the damage as pictured on the webpage: identifying ammunition and associated guns used, and types of aircraft associated with those guns --- and comments on the assumptions I've already made on the webpage, including my suggested scenario for Hole Nos. 1 and 2 of an aircraft pulling out of a dive while firing. I thank you for any assistance.