To increase your loco’s headlight brightness, try using silver heating/air conditioning duct tape and cut a small piece to cover the inside of the headlight housing. MANCO is one brand that is foil based and is very reflective. LGB’s bulb-surrounding insert is easily covered.
In passenger cars and loco cabs, I cover the inside roof with the reflective tape. The reflective tape holds its adhesion independent of outdoor temperature. The lighting difference is noticeable.
Wendell