What's the difference between tickets numbered 218 and those numbered 280?

The train/ticket with seat number 218 and the one with seat number 280 have different characteristics.

Typically, in Chinese rail networks, carriages are denoted by numbers starting from A (or 1st class) to Z (or last class), followed by row letters or numbers. Seat numbers within a carriage are designated as single digits or a combination of letters and digits.

Here’s what might be different:

• Carriage: If the first digit is different, it indicates that the train/carriages themselves have distinct seating arrangements.
  
• Class: Seats in the same cabin but with different seat numbers could indicate varying levels of service or luxury (e.g., soft-sleeper vs. hard-sleeper).
  
• Sitting arrangement: Seat numbers within a carriage might denote specific seats, such as window seats, aisle seats, or those near to/blocked from exit doors.
  

To be sure about the exact differences between 218 and 280 train tickets in your case, I’d recommend consulting relevant travel documentation or seeking guidance directly with the railway agency.