Simplify the following text for a Grade 5 native English-speaking person.
Original: It is the only station on the Morden branch of the Northern line whose name begins with a vowel and is one of only two stations on the London Underground with only four letters in its name ( the only other being Bank ) .
Simplified: It is the only station on the Morden branch of the Northern line whose name begins with a vowel . It is one of only two stations on the London Underground with only four letters in its name .