Question about visibility on Steam Locomotives

If you are looking strait out the engineers window on a Pacific type steam locomotive on strait and level track how far from the front of the engine would someone standing between the rails of the track the engine was on have to be standing until they were visible to the engineer?

In otherwords I am asking how big is the blind spot created by the boiler with the centerline of the track?

From the engines I have looked out of the blind spot seemed to be 5 to 15 feet but I might have remembered this wrong. On a large pacific or hudson I think 15 feet. Remember I am speaking about strait and level track.

5 to 15 feet??
more like several hundred feet..
lets see..we need a drawing..hold on.

ok..im back.
I dont have any top-drawings of locomotive..
but I have side and front drawings of a LV classJ 4-6-0.
slightly smaller than a hudson or Pacific..
im getting a "blind spot" of 115 feet based on the dimensions of the 10-wheeler..a Hudson or Pacific would be even farther.
probably 150 feet or so.

http://img49.imageshack.us/img49/8919/blindspot2dg.gif

Scot

The diagram submitted makes an assumption that the line of sight off the front engineers window would be the same as if I stood next to a building Looking along a wall and asked somebody to stand 2 feet from the corner and walk outwards. If I did that I think your measurement would be dead on. I have a question in my mind if the line of sight off a steam engine actually behaves that way. Thank you for your time and consideration I don't dispute anything you submitted it is very good work.

Howard

why wouldnt the line of sight be that way for a steam locomotive?
the engineer could lean out of the cab a bit to gain some visability,
but that long boiler is solid..cant see around it or through it.

the only way the engineer could see "closer" in front of the boiler would be if he got farther away from the cab off to the side..
or closer to the front of the engine, by walking down the walkways on the side of the engine..
cant really do either from the cab of a moving locomotive..
Scot

I saw a 1933 vintage film about FDR a few months back, and part of the film was an action shot of the push rods and drivers of a steam loco. The camera was mounted about where the ladder would be to climb out of the cab, and it was shooting forward. You do see both rails ahead of the engine. With stop motion one could come up with a pretty decent idea of how far the blind spot is. This shot appears several times in the movie and it is clear.

If I see it again I will make a note of the title.

The reason why the line of sight is not going to behave the same as looking down the side of a building is caused by the running board and looking down a curved tube. Your drawing has the line of sight not touching the corner of the boiler it should because the boiler is curved. If you do that the visibility for center line of track should come out to about 40 ft. 115 ft would cover the distance needed to see someone standing on the outside of the rail on the fireman's side.

I measured the visibility on a 40 ft boiler and centerline of track is visible at 50 feet.

from the end of the running board walking strait out is 17 feet.

and standing on the fireman's side 105 feet.