Dartrider is correct, that is an arn setting with the running number's color.
Looks like the attachment point is to far in, to close to the position and it is cutting off the edges of the Lamp Flare.
That would be an issue with the creator to fix. I can move them out a bit to remove that cut off point, but it is not my asset to edit unless the creator gave me permission to do so. It is adjustable in the body .im file under the light attachments, if it is a trainz.mesh then it can not be adjusted.