Maybe this is old news around here, but I didn't see anything in searching.
There was an article in Model Railroader a few issues back covering different paint types. And who would know better about colors originally used for model railroad stuff. At any rate here is what had to say on replacing those discontinued colors...
MicroMark has a line called MicroLux created for them by Vallejo. It features 28 colors divided into two groups. The "Top 10" colors (Reefer White, Aged Concrete, and Engine Black among others) are sold in 2 oz bottles with the Microlux branding. The remaining 18 are offered in 1/2 ounce eye-drop-style bottles with a Acrylicos Vallejo Air label.
(Here's the important part ) All of the colors match the discontinued Poly Scale line
The paint can be airbrushed straight from the bottle without thinning, but can be thinned with alcohol or water and dry to a flat finish
Apparently they are only available through direct sales from MicroMark though
Here's Refer White
MicroLux Acrylic Paint, Reefer White, 2 Ounces
Grimy Black
MicroLux Acrylic Paint, Grimy Black, 2 Ounces
Roof Red
MicroLux Acrylic Paint, Roof Red, 2 Ounces
Here's the rest of the line
MicroLux Paints
Vallejo Paints
There was an article in Model Railroader a few issues back covering different paint types. And who would know better about colors originally used for model railroad stuff. At any rate here is what had to say on replacing those discontinued colors...
MicroMark has a line called MicroLux created for them by Vallejo. It features 28 colors divided into two groups. The "Top 10" colors (Reefer White, Aged Concrete, and Engine Black among others) are sold in 2 oz bottles with the Microlux branding. The remaining 18 are offered in 1/2 ounce eye-drop-style bottles with a Acrylicos Vallejo Air label.
(Here's the important part ) All of the colors match the discontinued Poly Scale line
The paint can be airbrushed straight from the bottle without thinning, but can be thinned with alcohol or water and dry to a flat finish
Apparently they are only available through direct sales from MicroMark though
Here's Refer White
MicroLux Acrylic Paint, Reefer White, 2 Ounces
Grimy Black
MicroLux Acrylic Paint, Grimy Black, 2 Ounces
Roof Red
MicroLux Acrylic Paint, Roof Red, 2 Ounces
Here's the rest of the line
MicroLux Paints
Vallejo Paints