I actually got the ones seen on the inside of Tube carriages about next symbols or letter in a series. But the minute I'm asked about "if" something usually travels or moves at "y", then when would "z" happen, something in my brain disconnects and I can't do it. I want to say 59 minutes but I know that seems too obvious and there's going to be some trick about British Summer time or clocks going forward or the Tube not having a timetable anyway.
Visting the site (at time of writing) currently provides no answer either, but there are more puzzles involving moving matchsticks, joining dots with the fewest number of straight lines and working out next symbols in series. Maybe the answer will be revealed later today, or in the following weeks. Although I'm sure tons of you will know the answer anyway.
It would be good to see more train related brain teasers to pass away a few minutes staring across a platform. Perhaps the next ads will be placed around Stratford and ask how long you have to wait for the next train during the London Olympics based on the probability of TfL's latest predictions having various degrees of accuracy. Or how to make a journey from x to y using as few of the Olympic hotspot stations as possible - now that would a brain teaser.