The Brightness of Headlights during 1930s to 50s

578 views
16 replies
1 rating 2 rating 3 rating 4 rating 5 rating
  • Member since
    April, 2018
  • 8 posts
The Brightness of Headlights during 1930s to 50s
Posted by Jones1945 on Monday, July 09, 2018 10:29 PM

I have been searching information about The brightness of a headlight bulb which steam locomovites were using during 30s to 50s but I only can find some advertisments of Headlight company which sold Locomotive Headlight with a "250,000 candlepower" light bulb inside the headlight. Take PRR as an example, I have seen a lots of pic showing K4s, M1s, Js only had a tiny light bulbs which looks like a 40 watts incandescent bulb inside a prewar model Headlights with a larger reflector, post war engines like the S2 turbine, Q2, K4s with Headlight above the smoke box only had a much smaller headlight without light reflector inside, only painted white inside. I would like to know if there was any law about the Headlight brightness of the States's railroads? Did railroads in 40s used light bulbs below 100 watts to cut cost? Thank you very much!  Yes

  • Member since
    December, 2017
  • From: I've been everywhere, man
  • 670 posts
Posted by SD70Dude on Tuesday, July 10, 2018 1:39 PM

Many (most?) steam locomotives had a 32V DC electrical system.  Not sure how that originated or how it was chosen. 

The steam turbine-driven dynamos on those engines can put out a lot of power, and are perfectly capable of powering bulbs which appear just as bright as those on modern diesels. 

But speaking of PRR headlights, their GG1 electrics in particular were known for having headlights that were never bright enough, from a crew's point of view at least.

Greetings from Alberta

-an Articulate Malcontent

  • Member since
    August, 2010
  • From: Henrico, VA
  • 8,322 posts
Posted by Firelock76 on Tuesday, July 10, 2018 5:12 PM

Just speaking of personal experience, for what it's worth, thirty-plus years ago we went for a ride on the steam-powered Morris County Central, a now-defunct tourist line that operated out of Newfoundland NJ.  Crying

Anyway, it was a night-time ride called "The Moonlight Special."  As the locomotive  ( A 1907 Baldwin product if I remember correctly) made it's dramatic approach to the station someone said over the stations loudspeaker  "Do NOT look directly at the locomotives headlight!  It's as bright as the sun!"

Whether or not it was original equipment or not I don't know, but that announcer wasn't kidding! 

That was a fun ride, by the way! 

  • Member since
    April, 2018
  • 8 posts
Posted by Jones1945 on Tuesday, July 10, 2018 9:15 PM

Firelock76
Anyway, it was a night-time ride called "The Moonlight Special."  As the locomotive  ( A 1911 Baldwin product if I remember correctly) made it's dramatic approach to the station someone said over the loudspeaker  "Do NOT look directly at the locomotives headlight!  It's as bright as the sun!"

Whether or not it was original equipment or not I don't know, but that announcer wasn't kidding! 

That was a fun ride, by the way! 

 

SD70Dude

But speaking of PRR headlights, their GG1 electrics in particular were known for having headlights that were never bright enough, from a crew's point of view at least.


Thank you very much! It seems that difference railroads had difference standard in the past. Milwaukee Road Hiawatha installed additional mar lights on their Class A and F7 Hudson in late 40s, almost at the same time period, PRR also added an small auxillary headlight on some of their K4s and all(?) of their T1s (but their GG1, PA and centipede etc still only had the original single headlight) NYC's Niagara had the headlight conversion (from single headlight to duel beam) in Nov, 1948, I wonder what was the reason behind these changes. Idea 

  • Member since
    September, 2003
  • 5,673 posts
Posted by Overmod on Sunday, July 15, 2018 11:32 AM

Much more to this.

Mars/Gyralites, etc. in that era had little to do with brighter headlighting; I have seen rotating sweep lights that spotlighted a much larger section of view but such an effect would be largely wasted on steam with long boilers or other impediment to forward visibility.  Many of the red Mars-type lights were to show stoppage or UDE on multiple-track routes rather than grade-crossing safety.

As I recall, the Pyle dual-beam lights used postwar on NYC power were primarily intended to keep a light burning if one bulb went out.  A number of early E units featured a rosette of sealed-beam units in the hole of a reflector light; this gave about as bright a light as a non-arc light could produce from such a location.

Many GG1s were given dual sealed-beam conversions (not protruding as the Pyle conversions for steam headlight casings were) and very late, so were a number of B&O engines.  I have documentation of at least one PRR T1 with vertical sealed-beam conversion (in 1948) and to me this really improves the look of the 'second-generation' production front end.

  • Member since
    September, 2003
  • 5,673 posts
Posted by Overmod on Sunday, July 15, 2018 11:36 AM

There is still some research going on as to what the T1 'auxiliary' light does.  It does not oscillate, and it is not colored, so the supposition that it is a 'fog' light closer to the track in poor visibility may be correct.

  • Member since
    August, 2010
  • From: Henrico, VA
  • 8,322 posts
Posted by Firelock76 on Sunday, July 15, 2018 7:30 PM

I mentioned the Morris County Central a bit earlier, care to see a bit of it?

First is a mid-sixties commercial...

https://www.youtube.com/watch?v=MkWzvVItgss

And  a railfan home movie shot in 1974.

https://www.youtube.com/watch?v=V6Ac4aXRY9A

It was a fun ride!

  • Member since
    April, 2018
  • 8 posts
Posted by Jones1945 on Monday, July 16, 2018 10:15 PM

Firelock76

Time flies, but memories last forever!Cool

 

Overmod

Much more to this.

Mars/Gyralites, etc. in that era had little to do with brighter headlighting; I have seen rotating sweep lights that spotlighted a much larger section of view but such an effect would be largely wasted on steam with long boilers or other impediment to forward visibility.  Many of the red Mars-type lights were to show stoppage or UDE on multiple-track routes rather than grade-crossing safety.

As I recall, the Pyle dual-beam lights used postwar on NYC power were primarily intended to keep a light burning if one bulb went out.  A number of early E units featured a rosette of sealed-beam units in the hole of a reflector light; this gave about as bright a light as a non-arc light could produce from such a location.

Many GG1s were given dual sealed-beam conversions (not protruding as the Pyle conversions for steam headlight casings were) and very late, so were a number of B&O engines.  I have documentation of at least one PRR T1 with vertical sealed-beam conversion (in 1948) and to me this really improves the look of the 'second-generation' production front end.

 

 
Thank you very much! I didn't know that there was at least one T1 had its single headlight converted into a vertical sealed-beam! Was it a dual sealed-beam? I agree that the design of Headlights or its positing really affect the looks of an engine a lot, IIRC there were at least 3 conceptual design options of T1 provied by Raymond Loewy, one of them was a bullet shape smoke box design, another two was the "shark nose" smoke box design with smooth casting or stainless steel skin on the nose, these three designs had one thing in common which was the position of the Headlight. Unlike S1 and 5 streamlined K4s,  The headlights on these designs were on the top half of the "smoke box" which were similar to Q1's (#6130 4-6-4-4) original streamlined design, its seems that the leader of PRR in 1930s did care about where the headlight should be installed and where the Keystone number plate should be placed. (S1 didn't have a Keystone number plate at the front end, T1 "front end with port holes version" had the Keystone number plate installed below the smoke box but they were "put back" to the smoke box, below the headlight on the modified version ) T1 were designed to haul long distance express trains, I wonder if there was any regulation about the brightness of their engine's headlights, beside the design of its overall apperance.
 
(Pic 1: Models of T1s conceptual design, Source: online archive of Railroad Museum of Pennsylvania) 
Models of T1s Conceptual Designs
 
 
(Pic 2, A PRR K4s with its headlight turned on, Source: online archive of Railroad Museum of Pennsylvania) 
)
PRR K4s
 
Btw, judging base on the above pic taken in a cloudy day and some videos I watched, the postwar headlight model used by PRR seems smaller and quite dim! I am not sure if there was a reflector inside it or the brightness of the lights were ajustable, if the headlights used by post-war steam were just as bright as a 600 - 1000 lumens flashlight we use today, does that mean, at least for PRR, that the headlights of steam engine, especailly for the express engine were somewhat useless, it just functioned as a road safety device, similar to the British's railroad appoach in the same era? (( Idea ))
Tags: t1 , headlight , K4s , Q1 , Raymond Loewy , S1
  • Member since
    September, 2003
  • 5,673 posts
Posted by Overmod on Tuesday, July 17, 2018 11:28 AM

The T1 picture I have (at a coaling tower in Indiana) is indeed double sealed-beam, with the bulbs vertical (as in the GG1s that were converted).  It is possible (I have not yet found any drawings for the T1 conversion) that the mounting is the same basic or perhaps even detail design.  It appears to be the same idea of putting the two bulb mounts in a plate and installing this in the opening for the reflector mount.

I had very little experience with PRR reflector headlights EXCEPT to note that when the ones in E7s on the Bay Head line were on 'bright' and you were directly in line with the beam they were dazzlingly bright, about as bright as the sun to a 4-year-old watching from a car going across a grade crossing.  I in fact thought (by comparison with the sealed-beam lights on some of the RS units going through Tenafly on the Northern Railroad) that this had to be one of those fancy 7-bulb high-speed lights, until the locomotive motored past, in Tuscan glory ... with relatively dim headlight appearance to the side.

As with many laser applications, too much 'beam visibility' to the sides just shows that light's being wasted from the main purpose of illuminating the parts of the ROW the engine crew immediately needs to see.  These lights did have reflectors, and some care was taken to design them so that the brightest part of the filament in the bulb was at the geometric focus of the parabolic mirror.

On the other hand, of course there was a dimming function (or meets would have been dazzling just as an opposing crew would need reasonable detail vision to check the following train for problems).  I do not know whether this was done with resistors or simply by controlling the turbogenerator, but there are people here who will definitively know.  As you can readily imagine there is little use for the headlight as a road-illuminating device during the daytime, and particularly if regulated via turbogenerator speed (and hence steam mass flow conserved, which might be substantial) running dim in the daytime would have economy benefits, so I would not be surprised to find it was intended more as a safety device then.

  • Member since
    February, 2005
  • 1,715 posts
Posted by timz on Tuesday, July 17, 2018 12:12 PM

Think PRR E7s had brighter headlights than other E7s? Anyone got an E7 manual showing available choices?

  • Member since
    September, 2003
  • 5,673 posts
Posted by Overmod on Tuesday, July 17, 2018 12:44 PM

timz
Think PRR E7s had brighter headlights than other E7s?

Not at all, really!  Just noting that the ones I saw were single-bulb reflector lights, and EXTREMELY bright in the line of the beam.

All the seven-light arrangements I've seen were on older units (I think nothing more recent than an E6) and I don't know if these were 'factory' options or special order components.  The history of 'optical warning' of high-speed trains is an interesting subject (some details are covered in Kratville's book on the UP Streamliners) as at least some of the idea was to provide very bright beams either projected in front of trains or vertically into the sky like rotating premiere searchlights to signal motorists that Something Significant Was Approaching.  Since this was a prominent component of the later rationale for adoption of ditch lights, it may merit more attention than it has historically received.

One very probable reason for disuse of the seven-bulb headlight would be the FRA requirement that all bulbs be working 'as installed' on inspection.  Those familiar with the Southern Pacific's foray into safety lighting in the '60s will remember how that ended, with openings plated off ... and safety not at all enhanced.

  • Member since
    February, 2002
  • From: Mpls/St.Paul
  • 10,572 posts
Posted by wjstix on Wednesday, July 18, 2018 3:06 PM

You can't judge how bright a headlight is during the day, cloudy or not. I drive along a rail line (actually two mainlines running parallel) going to and from work every day. During daylight hours, you can hardly tell the headlights are on. At night, they're incredibly bright.

It's kinda like big league ballparks that shoot off fireworks when the home team hits a homerun. It's not very impressive during day games, much more visable at night.

Note too that headlights have more than one brightness setting, so can be on, off or dimmed by the engineer.

Stix
  • Member since
    May, 2003
  • From: US
  • 14,124 posts
Posted by BaltACD on Wednesday, July 18, 2018 6:32 PM

Remember - most railroad rule books require headlights to be in the dim position 

2014 CSX Rules
The headlight on the leading end of a train must be dimmed when:

a. Required to provide for the safety of employees, or

b. At yards where switching is being done, or

c. Approaching passenger stations where stops are to be made, or

d. Standing behind a stopped train, or

e. Standing on a main track in non-signaled territory, or

f. Approaching and passing a locomotive consist on the head end and rear end of a train on an adjacent track, or

g. Using hand signals.

         

Never too old to have a happy childhood!

  • Member since
    April, 2018
  • 8 posts
Posted by Jones1945 on Thursday, July 19, 2018 12:53 AM

Overmod
These lights did have reflectors, and some care was taken to design them so that the brightest part of the filament in the bulb was at the geometric focus of the parabolic mirror

wjstix
You can't judge how bright a headlight is during the day, cloudy or not.

Thank you very much for your very detailed response! I really apprecicate it and I mostly agree with you guys. I did try to find pics or evdiences of steam locomotives headlight at night from 30s to 50s, but I can only found some touched up photos which probably used for promotional proposes. Anyway the answer is more clearer for me now after reading you guys first hand experiences or professional knowledges about lightings. To sum up, headlights of steam engines in the past was like a flashlight we use nowadays, it shoot a beam a long distance but does not necessarily light up all of the area close to the flashlight thus when people looks directly to it, it is as bright as the Sun, but it looks dimmer when people looks at it from the side. Assumes a headlight which had a light reflector installed, used a 100 watt (about 1000 lumens) incandescent bulb inside, I believe it was still bright enough during extreme weather at brightest mode, I have seen how a 1000 lumens flashing can do on youtube, its actually very bright.

(Pic 1: A PRR K4s headlight shooting lights beam at night. Source: online archive of Railroad Museum of Pennsylvania) 

K4s shooting light beam at light

(Pic 1: Headlighs of T1 5550 underconstruction, Source: http://www.wikiwand.com/en/Pennsylvania_Railroad_5550 

The prow of PRR 5500

Idea ==== Cool

  • Member since
    September, 2003
  • 5,673 posts
Posted by Overmod on Thursday, July 19, 2018 5:24 AM

Jones1945
Assumes a headlight which had a light reflector installed, used a 100 watt (about 1000 lumens) incandescent bulb inside, I believe it was still bright enough during extreme weather at brightest mode, I have seen how a 1000 lumens flashing can do on youtube, its actually very bright.

Headlight bulbs were brighter than that.  Considerably brighter.  Modern 'standard' voltage is 74, but some older systems that 'charged' at 72V nominal only provided 64V nominal battery voltage to devices such as lighting.  Steam turbogeneration was (as I recall) generally in about the 32V peak range.  Bulbs however are rated in watts (for a given nominal voltage) in indicating the I2R power dissipation and hence the candlepower/'lumen' output of the incandescence. 

Current PAR56 sealed-beam lights, per FRA (see 49 CFR 229.125) are 350W and produce 6200 nominal lumens initially (the light output degrades somewhat over the 500-hour nominal life of the lamp).  Multiply this by two for the headlight, then add two for the ditch lights.  It is common to see a SI equivalent, usually 200,000 candelas, used for the bulb's nominal light output.

Of course when the light is on 'dim' the light output is much lower...

The 'standard' GE headlight bulb for steam applications was as I recall the 250P25 32V.  (The size code represents 25 eights of an inch diameter, and P is a round envelope shape.)  Initial output is 4650 lumens with nominal 500 hour life.

Incidentally, that second picture is not of T1 5500, it is the 'replica' prow that has been constructed for the T1 Trust.

  • Member since
    February, 2005
  • 1,715 posts
Posted by timz on Thursday, July 19, 2018 12:23 PM

6200 lumens would be the bulb's total light output -- 200000 candela refers to the light intensity within the beam, lumens per steradian or some such thing.

  • Member since
    April, 2018
  • 8 posts
Posted by Jones1945 on Thursday, July 19, 2018 12:35 PM

Overmod

The 'standard' GE headlight bulb for steam applications was as I recall the 250P25 32V.  (The size code represents 25 eights of an inch diameter, and P is a round envelope shape.)  Initial output is 4650 lumens with nominal 500 hour life.

Incidentally, that second picture is not of T1 5500, it is the 'replica' prow that has been constructed for the T1 Trust.

Thank you for correcting me Overmod, I can't believe I forgot the number of the T1 building by T1 Trust is 5550 not 5500! IdeaSpeaking of T1s, I remember in the book "Black Gold - Black Diamonds: The Pennsylvania Railroad & Dieselization" by Eric Hirsimake, one of the problem T1 6110,6111 had were the sockets vibreated loose caused headlight bulbs failed.

By the way, a 4650 lumens headlight with light reflector inside it must be very dazzling! One of the reason I am interested in this topic because I always think that Steam locomotive running at night with its headlight turned on is a very cool thing. I remember when I was a kid, I always draw steam engine on a sketchbook (even though I hadn't seen a steam engine in person until I grew up), adding headlights, paint the light beam in yellow on my fantacy steam engine was one of the funniest thing for me. Thank you very much for providing the light bulb model, with more keywords and details, I can't dig deeper on this topic. Thumbs Up Idea

timz
6200 lumens would be the bulb's total light output -- 200000 candela refers to the light intensity within the beam, lumens per steradian or some such thing.

Thanks! I just watched a video demonstrate how powerful is a 6200 lumens flashlight on youtube, thats "crazy bright"!

SUBSCRIBER & MEMBER LOGIN

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

FREE NEWSLETTER SIGNUP

Get the Classic Trains twice-monthly newsletter