It could help in making a child try a transport system (4,4)
I believe the answer is:
test tube
'it could help in making a child' is the definition.
The definition suggests a singular noun which matches the answer.
'try a transport system' is the wordplay.
'try' becomes 'test' (test is a kind of try).
'a transport system' becomes 'tube' (I've seen this before).
'test'+'tube'='TEST-TUBE'
Can you help me to learn more?
(Other definitions for test tube that I've seen before include "useful for experiment" , "glass vessel" , "Item of laboratory equipment" , "Small glass cylinder with one end closed, used in laboratory" , "Laboratory experimental container" .)