[smallspy]

Saw a T1 with new LED headlights this morning on Line 2. Just a new part, or part of a broader refurb?

They've been retrofitting LEDs into cars over the past 4 or 5 years as the different lights and components fail. A number of cars have full or partial LED interior lighting, for instance.

Dan
Toronto, Ont.

 

[TheTigerMaster]

I really don't like the blueish LED lighting in the T1. They should use whatever is used in the TR.

 

[W. K. Lis]

I really don't like the blueish LED lighting in the T1. They should use whatever is used in the TR.

LED's come in different colour temperatures. This is measured in degrees Kelvin.

The old incandescent light bulbs were around 2,700K.

Kelvins	Type
1,000K	Candlelight Red/Yellow	Very Warm
2700K	Conventional Lamp - Yellow	Warm
3000K		Warm White
4000K	Halogen/CFL - Blue	White
5000K		Cool White
6000K		Daylight
10,000K	Blue Sky - Blue	Very Cool

Because the trains are going outdoors, they'll want the headlights to cast the same colour temperature in the tunnels as the daylight outdoors.

Try comparing navy blue socks and black socks under the old incandescent light bulbs at night and the daylight shining through a window.

 

[TheTigerMaster]

I was talking about the interior lighting in the vehicle. Perhaps they were trying to go for a "natural light" feeling?

 

[Johnny Au]

Don't forget that Kelvins are not in degrees, unlike Celsius or Fahrenheit.

 

[AlvinofDiaspar]

Don't forget that Kelvins are not in degrees, unlike Celsius or Fahrenheit.

Actually at those black body temp the difference (273K) is rather academic.

AoD

 

[W. K. Lis]

Don't forget that Kelvins are not in degrees, unlike Celsius or Fahrenheit.

Actually, Kelvin is degrees from absolute zero. A Celsius degree is equal to a Kelvin degree in magnitude. See link.

The kelvin is often used in the measure of the colour temperature of light sources. Colour temperature is based upon the principle that a black body radiator emits light of which the colour depends on the temperature of the radiator. Black bodies with temperatures below about 4000 K appear reddish whereas those above about 7500 K appear bluish. Colour temperature is important in the fields of image projection and photography where a colour temperature of approximately 5600 K is required to match "daylight" film emulsions. In astronomy, the stellar classification of stars and their place on the Hertzsprung–Russell diagram are based, in part, upon their surface temperature, known as effective temperature. The photosphere of the Sun, for instance, has an effective temperature of 5778 K.

 

[DarnDirtyApe]

I was talking about the interior lighting in the vehicle. Perhaps they were trying to go for a "natural light" feeling?

I've also noticed a blue-ish tint to the interior lighting in some trains. I suspect that they went for "daylight" LEDs, which are brighter and also tend to be more commonly available than "warm" LEDs.

 

[smallspy]

I really don't like the blueish LED lighting in the T1. They should use whatever is used in the TR.

The TRs use modern T6 florescent tubes.

Dan
Toronto, Ont.

 

[TheTigerMaster]

Smallspy: the man who knows everything

 

[doug]

LED's come in different colour temperatures. This is measured in degrees Kelvin.

"White LEDs" are blue LEDs with a yellow phosphor, they work similarly to fluorescent tubes. As the phosphor ages and breaks down, the colour changes.

Kelvin is a unit of measure, there are no degrees kelvin.

 

[aquateam]

Actually, Kelvin is degrees from absolute zero. A Celsius degree is equal to a Kelvin degree in magnitude. See link.

What Johnny Au is saying is that when you're dealing with an absolute temperature scale, like Kelvin or Rankine, you don't use the word "degree". So you'd say the temperature is either 5 "degrees Celsius" or 278 Kelvin (no degree).

 

[W. K. Lis]

I've also noticed a blue-ish tint to the interior lighting in some trains. I suspect that they went for "daylight" LEDs, which are brighter and also tend to be more commonly available than "warm" LEDs.

"Warm White" LEDs are more common than "daylight" LEDs. I use "daylight" LEDs in my closet and bathroom, because it most simulates the outdoor light. I use "warm white" for the bedroom for the "warmth". The dining room uses "warm white" to get food more appealing look to the food. Hallways are "daylight", to check that our clothes will "look" right outdoors.

 

[DonValleyRainbow]

Well the interior lighting on the TTC will have nothing on Guelph Transit. Some of those buses aren't even bluish-white, they're straight-up blue.

EDIT - like this:

 

[AlvinofDiaspar]

Well the interior lighting on the TTC will have nothing on Guelph Transit. Some of those buses aren't even bluish-white, they're straight-up blue.

Not sure if they've considered the issue of LED blue light hazard.

AoD