1) The height beneath the

1) The height beneath the bridge should be easily adjustable by shortening the abutment walls. I#m not sure if these are parts in the kit. The instructions don't show them. And there is this sentenve from the Walthers bascule bridge website: Add to new or existing scenery with Single-Track Railroad Bridge Concrete Abutments (933-4551, sold separately) There are a number of photos like this: https://c1.staticflickr.com/9/8189/28224602893_e5134d3670_c.jpg

2) yes, see instructions: https://www.walthers.com/fileuploader/download/download/?d=0&file=attachments%2F09330000003070.pdf

3) According to Paul Mallory's Bridge & Trestle Handbook combined machinery house and operator's house in the A-frame were more often on railroad bridges. Street bridges had their operator's house usually at street level.
Regards, Volker

  gmpullman The "operator's

So it is both those little decks, AND those arms that make the bridge wider than the 3.25" quoted by Walthers?

Thanks for those pic's !

As I look back at those

As I look back at those photos I can see that things are symmetrical from side to side,...the little decks and swing arm attachments are the same on both sides. And from the looks of your ruler it appears the little decks stick out about 3/4" from the structure, and it appears the swing arms are likely about 1/2" proud?

So if I were to leave off the little decks and the swing arms on both inner sides of 2 closely adjoined bridge kits I would be saving about 2 x 3/4"=1.5 inches overall width of two side-by-side bridges (remember mine are specifically to be NONE operating, so I don't need those inner swing arms) . Does that sound correct?

If I left off the little deck on the outer side of one bridge against the wall, a) then I would have approx 1/2" for that swing arm there,....
b) then 3.25" for the bridge structure itself, ...
c) then zero between the bridges, ....
d) then 3.25" for the adjacent bridge,....

e) and the 3/4" projection of the little deck and the swing arm on the outer side of the pair.

So footprint down low at the base would be 3.25 +3.25?

I was looking at this idea of

I was looking at this idea of kitbashing 2 kits to make a double track lifting bridge. I think it could be done if the center frame was only one thickness thick rather then the two side-by-side with twice the frame thickness for that center frame. But then I believe that kitbash could only be a minimum of 3.75" + 4"= 7.75" wide.

This is NOT doable for my space, so I will drop this idea, and go with the double track swing bridge offered by Walthers.
 

Wish I had the space for 2 of the lift bridges side-by-side,...forget the kitbash.

Recalculations

I accepted those previous figures without checking them. Now that I had kind of given up on the idea, I thought first i need to go back and have another look at the dimensions of kitbashing 2 of them side by side.

First off realize I am NOT talking about an operating model, but rather the image of a double wide bascule bridge where BOTH sides rise and lower in unison. Here is the way I think it would work,

Looking back at these photos,..
 

What if we eliminate doubling up the two arms that would be next to one another when the two bridges were placed next to one another,..and eliminate the slight extra projection of that deck area. In other words we would only use ONE of those arms between the two bridges. 

That would result in the two long bridge sections would only be separated by that 1/2" wide singular arm that is being 'shared' by both bridges.

The track centerline on either of the bridges is in the middle of the total width of 3.250" or 1.625" from the inside edges. And the edges of these two side-by-side bridges is now only separated by 1/2" . So the centerline distances between the tracks on this combo dbl track bridge should be 1.625 +1.625 + ,5" separation beam width   = 3.750 inches. NOT so bad !!

Overall width of combo at outboard end would be 3.250 + 3.250 + .5  = 7"
Overall width of combo at the motor house/ counterweight end would be 4" + 4" + .5"   =8.5"
 

Any mistakes I made??