A vast number of bridge companies had their origins building railroad bridges. If a bridge company existed prior to 1900, you can be reasonably safe in assuming it built railroad bridges.

That does not mean that the company itself was a "railroad" company in the strictest sense of the word.

If a bridge company includes the word "railroad" or some sensible variation thereof, then I include it in my catalog of railroad certificates.

While bridge companies were meant to facilitate railroading, their main purpose was simply to bridge rivers.

One estimate suggests over 76,000 railroad bridges of all sizes were built in the United States alone. We could bump that number at least another 20,000 if we counted the rest of North America. It seems obvious that railroad companies built the vast majority of those bridges under their own corporate oversights.

Independent or semi-independent bridge companies, however, built many of the very largest bridges.

Strictly speaking, bridge companies were corporations separate from railroad companies.

So why did some railroad companies create separate bridge companies that built, managed, and maintained bridges while other companies did not? And why did some bridge companies seem unattached to any one specific railroad company?

A few bridge companies served multiple unrelated railroad companies. Tolls for passage across those bridges created revenue that retired bonds and loans and paid owners dividends.

Most bridge companies, however, were formed by single railroad companies to bridge rivers on the borders between two states or countries.

Many states required (and most still do) companies that operated within their borders to be officially incorporated within their borders. Obviously, multi-state incorporations created multiple layers of government oversight. That seldom made it easy for railroad companies to make profits.

By operating as separate companies, bridge companies were able to comply with multi-state (or multi-country) regulations and taxes without creating obligations on parent companies. It seems obvious that in order to comply with state regulations, bridge companies would have needed to operate as "arm's-length" companies, even if they were direct railroad company subsidiaries. That means that most bridge companies would have needed to install and maintain their own track and switches and maybe even switching equipment.

So should we consider bridge companies as "railroad" companies? In fact, did the bridge companies even consider themselves to be railroad companies? Without extensive research, we will never know for sure.

I need a simple answer. My goal is to list the certificates that railroad companies issued. My theory is that if railroad companies considered bridge companies as separate entities, then they remain separate entities for this catalog. By and large, bridge companies are NOT included in this catalog.

My rule then is to only list bridge companies when they include a word similar to "railroad" in their names

There are exceptions, of course. I reluctantly include a few companies by custom:

• Dunleith & Dubuque Bridge Co
• Louisville Bridge Co
• Louisville & Jeffersonville Bridge Co
• St Louis Merchants Bridge Co

These are bridge companies that most auction catalogers include among railroad company certificates. That makes their certificates easy to track.

However, if I had my way, I would not include any bridge companies in the database unless they included a word similar to "railroad." A few years ago, I polled my main contributors and they told me they wanted these few companies to remain in the catalog. So, at least for the time being, those few companies will remain.

No separate catalog for bridge companies? For those who would argue that there is no separate catalog for bridge company certificates, I invite you to take the opportunity to start one for yourself.