Little cumbersome to get to, but very interesting.  Found out that at one of the industries on my layout, they let bloodhounds loose at night.

So the answer to "who let the dogs out..." would be Walter Wann & Co.

GS

I got on the site and some of the 500,000 maps are already available and in color. Reading the information it appears that the goal the Library of Congress has set is to have the project completed in 2020, a very large undertaking.  This is a great resource for us as modelers, and I would hope that our readers would take advantage of the resource. Thanks for the lead, I know I will bookmark the site

Don 

Sanborn Insurance Maps are a good resource but have been hard to find in digital form.  This is great news

Lou in Utah

Sanborn map collection for New Hampshire is available at Dartmouth College Library at

https://libarchive.dartmouth.edu/cdm/search/collection/sanborn

http://researchguides.dartmouth.edu/c.php?g=59385&p=381713

These are mostly late 1800 to early 1900s (1920s)  They are downloadable at no charge

I've been trying to get Maine Sanborn maps but it appears you have to be a resident of the state to get into the Maine State Libraries.

BTW the Library of Congress Sanborn map project has been going on for years (10 yrs?)

Ed

wasn't important

Is there a good way to search through these maps? i have roughly a 10x10 room I'd like to build a switching layout in, based off some prototype or another, how would i search something like "1930s shortlines"? 

Sanborn maps are fire insurance maps.  They don't really care about railroads except to note they are there, so there isn't anyway to search by railroad.  The people that use them are people building, buying or insuring buildings, so they care about city and state.  That's how they are indexed.  For each city there is a master map that decodes which detail map covers which area of the city.

Basically you have to research which railroad you want, then which area you want, then look for that area in a Sanborn map.

Caveats.  Sanborn maps are NOT railroad maps so while they are pretty close, they are not exact as far as track arrangements go.  Not all areas have Sanborn maps, usually only heavily populated areas, smaller towns or more rural areas might have minimal insurance risk, so are not mapped.  Major industries (e.g. steel mills) are not necessarily mapped because the interior of the industry is all its own property and they are self insured.

As was mentioned several times previously, the Sanborn Fire Insurance maps are not railroad engineering maps, but I've found that they do match quote well with the engineering maps that I do have, as well as the USGS topographical maps.

The Library of Congress is on a long drawn out mission to digitize all of the Sanborn maps but they have a way to go. Here's a link to what they have on line so far:

https://www.loc.gov/collections/sanborn-maps/

They are normally organized by city, county, and state and the maps don't cover entire towns or cities, just the areas that were of interest to insurance underwriters back in the day. That said, they do contain interesting information about industries. For example, in the area that I'm modeling, the maps tell me about the height of the various on-line industries, their type of construction, whether the various mills had power plants with boilers, etc... There is a lot of information that can be gleaned from the maps.

Check them out. The LOC doesn't have all states on line yet, but they are working on it.

USGS topographical maps are great for finding right of ways, but they are not accurate at all as far as track arrangements.

Sanborn Maps can generally be found in local or regional libraries. In my case, the LOC has not yet made the Martinez, California maps available yet, but the county library and the county historical society both have them.

Keep in mind that the maps are a snapshot in time and are an excellent means of tracking changes over time because the maps were usually updated on a fairly regular basis.

FUNNY SIDE STORY: I was doing research at the county historical society one day, and while looking at a Sanborn map of the area I was interested in, a guy walks up and starts asking me what I was researching, and we started having a nice conversation, all the while he keeps staring at the map on the computer screen and looking more and more puzzled. I asked him a question about the particular lot in question and he replied, “You’re sitting on it” and walked off, never to be seen again by me. The historical society, which I already knew, sits on the very same lot as the 1904 building I was researching once stood.