File:ATSF El Capitan combined x3.png

AT&SF "Drumhead" logos from the El Capitan passenger trains.

AT&SF

El Capitan (train)

The entire logo is used to convey the meaning intended and avoid tarnishing or misrepresenting the intended image.

The logo is a size and resolution sufficient to maintain the quality intended by the company or organization, without being unnecessarily high resolution.

The image is placed in the infobox at the top of the article discussing [[El Capitan (passenger train) ]], a subject of public interest. The significance of the logo is to help the reader identify the organization, assure the reader they have reached the right article containing critical commentary about the organization, and illustrate the organization's intended branding message in a way that words alone could not convey.

Because it is a logo there is almost certainly no free equivalent. Any substitute that is not a derivative work would fail to convey the meaning intended, would tarnish or misrepresent its image, or would fail its purpose of identification or commentary.

Heralds are "logos" or "slogans" used by railroad companies and displayed on their equipment. Copyright does not protect names, titles, slogans, or short phrases. In some cases, these things may be protected as trademarks.... However, copyright protection may be available for logo artwork that contains sufficient authorship. In some circumstances, an artistic logo may also be protected as a trademark." Excerpt from http://www.copyright.gov/help/faq/faq-protect.html Use of such images on Wikipedia arguably meets Fair Use requirements.