04-02-2011, 03:57 PM
Ah hah, not so fast people. I was about to admit I was wrong until I looked at the photo closely.
If you carefully look at the inverted T beam, you cant actually see a top edge to it because it continues all the way up as a much larger depth beam than the long beams. So it now appears to me that the long beams butt into the deeper central support cross beam. This would also explain why the vertical I beams continue up past the bottom of the inverted T, to provide plenty of support for the beam under dynamic loads as trains cross. If you look at the inside edge of the vertical I beam on the left you will notice that there is a vertical plate and that this appears to continue across and fills in between all the other beams.
I also noticed that there are cross brace sections at what appears to be 1/3 of the span locations, whose purpose is to prevent the lateral beams from toppling sideways under load.
I will concede that it is difficult to determine what exactly is going on under the bridge given that the photo lacks sharpness due to lighting and the colour of the beams and years of dirt and grime. Perhaps a fresh photo using a good strong flash, aimed at the area in question might be in order.
The bridge itself is fairly old as it is made up of rivetted sections to make the various shapes, and as such I would estimate that it is a pre WW2 era bridge, possibly pre WW1.
I hope that this all helps with your excellent bridge building efforts.
Mark
If you carefully look at the inverted T beam, you cant actually see a top edge to it because it continues all the way up as a much larger depth beam than the long beams. So it now appears to me that the long beams butt into the deeper central support cross beam. This would also explain why the vertical I beams continue up past the bottom of the inverted T, to provide plenty of support for the beam under dynamic loads as trains cross. If you look at the inside edge of the vertical I beam on the left you will notice that there is a vertical plate and that this appears to continue across and fills in between all the other beams.
I also noticed that there are cross brace sections at what appears to be 1/3 of the span locations, whose purpose is to prevent the lateral beams from toppling sideways under load.
I will concede that it is difficult to determine what exactly is going on under the bridge given that the photo lacks sharpness due to lighting and the colour of the beams and years of dirt and grime. Perhaps a fresh photo using a good strong flash, aimed at the area in question might be in order.
The bridge itself is fairly old as it is made up of rivetted sections to make the various shapes, and as such I would estimate that it is a pre WW2 era bridge, possibly pre WW1.
I hope that this all helps with your excellent bridge building efforts.
Mark
Fake It till you Make It, then Fake It some More