• In our report on acoustical engineering and railway safety (3 May, p 20), we said buckled rails were thought to have been the cause of a fatal train crash in Sydney. However, the inquiry into the incident continues and the cause has not yet been determined. Transcripts of the hearing are available at
• Feedback reported that authors Glenn Fleishman and Jeff Carlson had to pay $15,000 for excess bandwidth when people downloaded their free book from their website (17 May). We now discover they “slipped in under the excess threshold” and “will not owe a cent”. Donations they received are being passed on to Project Gutenberg, which turns public domain titles into electronic books.
