ANAGRAM RIDDLE

[The two answers to this flat are anagrams.]

A beloved Christmas present, especially for boys
What this present often will do when boys grow to men

HINTS:
_ _ _ _ _   _ _ _ _ _
_ _ _   _ _ _ _ _ _ _

Initials of the fist answer:
M  T

Initials of the second answer:
L  D

Answers:

MODEL TRAIN
LIE DORMANT

Credit: The Enigma
NPL Magazine - June, 2012
WRYBOSH  (adapted)