Rewrite each original sentence in order to make it easier to understand by non-native speakers of English. You can do so by replacing complex words with simpler synonyms (i.e. paraphrasing), deleting unimportant information (i.e. compression), and/or splitting a long complex sentence into several simpler ones. The final simplified sentences need to be grammatical, fluent, and retain the main ideas of their original counterparts without altering their meanings.
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Question: On the 15 November 2003 a Sprinter train travelling to Ballarat was derailed between Ballan and Gordon injuring 61 people when it hit a stationary car on a country railway crossing.

Answer: A Sprinter train that was derailed between Ballan and Gordon injuring 61 people, when it hit a stationary car on a country railway crossing on November 15, 2003.

Question: The spot was observed at different times with different sizes and shapes.

Answer: The spot was seen at different times. It had different sizes and shapes.

Question: In 1961, she made her Metropolitan Opera debut as Aida; the following year she made her debut at the Royal Opera House with the same role.

Answer:
In 1961, she made her Metropolitan Opera debut as Aida. In 1962, she made her debut at the Royal Opera House playing Aida again.