Peyton,
I have scanned many large D&RGW drawings for my book and article projects. I like to scan high resolution as many of the drawings have dust spots, stains, etc. and the higher resolution makes editing easier. I create a blank Photoshop file that is a bit larger than the drawing. I scan the drawing in two parts and then paste the two parts into the blank file as layers. I can then move the two parts so they align. After they are aligned, I compress the layers so it is one file. I can then crop off any extra space around the edges.
I have several original D&RGW profile books from the 1930s that were gifts from Jack Thode and they are too large to scan as one image.
I was training and technical publications project manager for Hewlett-Packard Scanjet scanners for 7 years and did this kind of scanning often. It is time consuming, but not that hard
Another possibility might be to get the electronic version of the Gazette as I think they are already in PDF format.