Simplify the following text for a Grade 13 native English-speaking person.
Original: As c2c is mainly a London commuter railway and the normal c2c journey is between 40 to 70 minutes , c2c does not have first-class seating : all of its Class 357 trains are fitted with standard high-density 3 +2 Chapman seating to meet demand at peak times when the line is very busy .
Simplified: As c2c is mainly a London commuter railway and the average c2c journey is between 40 to 70 minutes , c2c does not offer first-class seating : all its Class 357s are fitted with standard high-density seating to meet demand at peak times when the line is very busy .