Amy and Rory are passengers on a train that is moving through a long straight tunnel at a velocity of β = 3/5 in the +x

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Amy and Rory are passengers on a train that is moving through a
long straight tunnel at a velocity of β = 3/5 in the +x direction.
Amy and Rory are separated a distance of 80 ns of distance as
measured from the tunnel (rest frame). At a pre-arranged instant of
time in the train frame that we call t′= 0. Amy reaches through her
window and paints a marl on the tunnel wall (event A) and Rory also
reaches through his window and paints a mark on the wall (event B).
Let Amy’s define the spatial origin x′= 0 in the train
frame.
(a) Construct a calibrated spacetime diagram of the situation
described. Draw Amy and Rory’s worldlines, locate evens A and B,
and draw the worldlines of the marks. (Remember that the marks do
not exist before events A and B.)
(b) What is the distance between events A and B as seen from the
train frame? Do this using the spacetime diagram, and using Lorentz
transformation equations.
(c) Read from your diagram the displacement ∆x between the marks in
the tunnel frame, and show with lines and labels on the diagram how
you arrived at that result.
(d) How is it possible for Amy and Rory, who are 80 ns apart in the
tunnel frame, to paint their marks simultaneously and yet leave
marks on the tunnel that are more than 100 ns apart? Explain in
quantitative detail how everything works in the tunnel
frame, assuming that Amy and Rory really do make their marks
at the same time in the train frame.