Atlas Master/Silver series loco light bulb recomendations

[Charlie B]

Looking for recommendations (size, rating and source) for an Atlas HO Master/Silver series diesel locos forward and reverse bulb.  I'm looking for direct one for one replacement of the grain of wheat style lights.   NOT looking to switch led at this time.  Here is a picture of the current one barely glowing (below)

Thanks

Are you running DCC? if so there may be a CV to set for brightness on the bulb. 
Charlie