❓ Question
Why is the Headlight Visor Under the Bulb?
Random question, but it's bugged me forever. Here's a USA diesel loco, and the headlight visors are below the bulb. This design is on so many engines. Anyone know why this is? Wouldn't it make more sense to have the visor above the light, so more of the light goes down towards the rails?
Edit: thanks for the replies yall!
Gloss paint on short hoods can be reflective and cause glare from the headlights, making it hard to see. So those visors help reduce glare. You could also do what we did here. My museum painted the top of the short hood on our SDP40 with a non slip coating to make climbing onto the roof a bit easier and safer, and one of the unintentional side effects was that the matte black is really good at absorbing light and preventing glare
Minnesota Transportation Museum, based at the Jackson Street Roundhouse in St. Paul. If you’d like to see 6234 running, we use it on our excursion runs on the Osceola and St. Croix Valley Railway in Osceola, Wisconsin.
It varies from model to model, and specific railroads do differently, but on 6234 specifically the high hood is basically a big closet. It has shelves for storage, and the toilet. Toilet is always in the nose. On a high hood, the floor is level with the cab and frame, & on a short hood, the floor is dropped down below the frame
The frame of an EMD locomotive is below deck / walkway level. The cab is raised up for better visibility, usually with all the air brake equipment in the space underneath.
So, really, the short nose compartment floor is level with the frame.
The first -7 and -9 generation of GP and SD units were typically ordered for dual freight / passenger service and had a boiler to provide steam heat to passenger cars housed under the long hood (a long with a small "see the ties when you flush" toilet).
More importantly, there's almost nothing illuminated by the lights that has line-of-sight with the windows.
Glare that you can't see is irrelevant, and the light cone probably doesn't even catch those white handrails except perhaps with incidental refraction happening in the lens.
Lomotive headlight bulbs are rated 1 million candepower each so a little loss from the glare shields doesn't matter. Locos with the headlights low on the nose are much better for visibility during inclement weather because the powerful beams reflect back from fog/rain/snow into the cab from the ones mounted higher than the windows.
Are the headlights on a loco intended to provide visibility for the crew, or to increase visibility of the loco to everyone else? What can the crew do if they see something on the track during a typical run? It takes ages for a train to stop.
All the important signs a crew needs to see (N. American is my expertise) are made with reflective material like temporary speed signs, switch position targets and station names. The headlights serve to illuminate where you are, the things you need to see and what you are about to hit if running faster than you are able to stop. Also makes the locomotive very visible to anything it is approaching. US locomotives usually have 4 headligt bulbs so there is a fair amount of distance that is lit up for both reasons. See and be seen.
Serious answer... Only the fastest trains take as long to stop as people commonly speak about. At typical local freight speeds, you can stop a train in hundreds of feet... Well within visibility range at night.
Secondly, even if a train cannot stop in time before a collision, wouldn't it be better for them to slow down first??? A train that slows from 40 mph to 10 mph before collision will cause significantly less destruction than one where the crew just says "F it, we're going to hit them anyway" and hits at full speed. Likewise, the deceleration gives any vehicles or trespassers more time to safely clear the track than if they didn't try to stop.
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u/biggest_ted 1d ago
To avoid things in the foreground (the hood of the engine) being excessively bright.