Most top quality locos are lubricated
sufficiently when they are assembled. Ninety nine times out of a
hundred, if treated with respect, a model will never need
lubrication again.
Be very sparing with lubrication of a model, and preferably
let an expert decide whether any lubrication is required, and then
let the expert do it.
Remember, if not done correctly, lubrication is a
magnet for dust and grime, which turns into an excellent grinding
paste that WILL shorten the life of the loco.