more about:

My first step was to analyze the, now almost unaccessible, signs by using some photos I had taken on a morning walk across the bridge last summer. [might I also note that walking across the old bridge was quite a wonderful experience]

Just by visual analysis, you can see that there are essentially 2 stem thicknesses, and 2 letter widths [e.g. E, F, and T have the lesser width, which H and V are the wider]. Instead of just assuming that, I measured it.

Using Photoshop, I flattened the perspective so I could more accurately analyze measurements using the Ruler tool.

Once I had the letters sketched out on paper, I drew them in Adobe Illustrator, but attempted to recycle as many characters as possible. For example, I made the J by reflecting the G and slightly modifying dimensions, the U from the O, V from A, etc.

Of course, looking back, it may have been much simpler to draw the font in Fontlab [program I used to make the font file]... but so it goes.