Class 707 tail lights

[E_Reeves]

Hi all,

I was recently reviewing my pictures from when I went to Reading a couple of weeks back to see the 707s. In one photos I noticed that the tail lights weren't illuminated on one of the units.

As it was a picture, I'm not sure if they were out only for a few seconds or they weren't even turned on. Would there be anything that means the lights go out for few seconds or were they not even switched on?

Thanks

 

[tsr]

I don't know what systems 707s have in place, but certain classes of rolling stock do have the ability to have the wrong lights (or no lights) set. If they're anything like 700s then this may be deceptively easy. It's not long ago that I experienced one or two 700s leaving stations with tail lamps showing at the wrong end (suitably corrected or quietly flagged up as needed, of course).

However, all that being said, I suggest it was quite possibly a camera issue, as some have problems picking up LED lights of various types, including some tail lamps. Try taking some photos of a station departure board, of the type comprised of a matrix of LEDs, and see if some dots are missing. If so, your camera probably isn't picking up everything which your eyesight would.

 

[E_Reeves]

However, all that being said, I suggest it was quite possibly a camera issue, as some have problems picking up LED lights of various types, including some tail lamps. Try taking some photos of a station departure board, of the type comprised of a matrix of LEDs, and see if some dots are missing. If so, your camera probably isn't picking up everything which your eyesight would.

It picked up the tail lights in previous pictures

 

[tsr]

It picked up the tail lights in previous pictures

Not wishing to ask silly questions, but were you perhaps shooting at a different angle, with different settings or in slightly different light? Perhaps you stepped out from the shade of a station canopy, or swung the angle a little whilst tracking the train? This is exactly what's resulted in some of my photos not showing illuminated tail lamps, if I remember correctly.

 

[dosxuk]

LEDs are often pulsed on and off (and they don't have a cool-off or warm-up period, fading between states) as this saves energy and reduces heat build up, meaning they last longer. If this is done at a low enough frequency (which is very common), it'll be slower than the time taken by a camera to capture a frame - so they can randomly appear on or off on the camera, but constantly on to your eyes.

If you're recording video, you'll often see the LED coming on and going off at a slow rate (less than once a second) as the time the LED switches on/off interferes with the rate the camera is capturing. I think there have been a couple of examples posted on here where people have filmed flashing signal lamps which don't flash in real life.

 

[E_Reeves]

Not wishing to ask silly questions, but were you perhaps shooting at a different angle, with different settings or in slightly different light? Perhaps you stepped out from the shade of a station canopy, or swung the angle a little whilst tracking the train? This is exactly what's resulted in some of my photos not showing illuminated tail lamps, if I remember correctly.

Could well be. I always leave my camera on auto, but I did step out of the shade, as it was at the end of the SWT platforms.

LEDs are often pulsed on and off (and they don't have a cool-off or warm-up period, fading between states) as this saves energy and reduces heat build up, meaning they last longer. If this is done at a low enough frequency (which is very common), it'll be slower than the time taken by a camera to capture a frame - so they can randomly appear on or off on the camera, but constantly on to your eyes.

If you're recording video, you'll often see the LED coming on and going off at a slow rate (less than once a second) as the time the LED switches on/off interferes with the rate the camera is capturing. I think there have been a couple of examples posted on here where people have filmed flashing signal lamps which don't flash in real life.

Well, I took 3 pictures in the same place, all showing the same thing.

 

[AnonymousUser1]

LEDs are often pulsed on and off (and they don't have a cool-off or warm-up period, fading between states) as this saves energy and reduces heat build up, meaning they last longer. If this is done at a low enough frequency (which is very common), it'll be slower than the time taken by a camera to capture a frame - so they can randomly appear on or off on the camera, but constantly on to your eyes.

If you're recording video, you'll often see the LED coming on and going off at a slow rate (less than once a second) as the time the LED switches on/off interferes with the rate the camera is capturing. I think there have been a couple of examples posted on here where people have filmed flashing signal lamps which don't flash in real life.

like the film / video of the helicopter with 'static' rotors becasue the rotational spped ofthe rotor and the shutter speed of the camera are in sync

 

[GW43125]

LEDs are often pulsed on and off (and they don't have a cool-off or warm-up period, fading between states) as this saves energy and reduces heat build up, meaning they last longer. If this is done at a low enough frequency (which is very common), it'll be slower than the time taken by a camera to capture a frame - so they can randomly appear on or off on the camera, but constantly on to your eyes.

If you're recording video, you'll often see the LED coming on and going off at a slow rate (less than once a second) as the time the LED switches on/off interferes with the rate the camera is capturing. I think there have been a couple of examples posted on here where people have filmed flashing signal lamps which don't flash in real life.

Class 68 headlights are a very good example of this.

 

[ComUtoR]

If they're anything like 700s then this may be deceptively easy. It's not long ago that I experienced one or two 700s leaving stations with tail lamps showing at the wrong end (suitably corrected or quietly flagged up as needed, of course)

Take off key, lights go red.

 

[E_Reeves]

I found a video that I took when it departed as well, and the tail lights don't show up on there either.