During the Passenger train era there were certainly brakemen on passenger trains, even the premier trains of the road.
While the Internet is poor at finding factual information, other than discussion on the current argument over train crew size, I was able to find a site that reinforces my memory on the subject:
"Freight trains of this era normally carried two brakemen, one on the head-end, riding in the locomotive's cab, and a "flagman," which rode in the trailing caboose. Each man had very serious responsibilities that included protecting the train through roll-by inspections (watching for hot boxes or some other problem with the equipment) and physically walking down the tracks to warn approaching trains of a problem (remember this was during the era long before radio or other wireless communication devices)..."
While this specifically mentions freight, the crew size was mandated, and the front and rear brakemen on passenger trains were more less the conductor's assistants; the conductor ruled the train, and brakemen would extend his capability, as well as undertake operational tasks along the journey and in station. One common place to observe the brakeman was collecting orders along the line, often suspended on posts or passed up in long handled hoops.
The best advice is as always; find what specifically interests you, such as railroad, era, train, etc., and research the heck out of it.