Question 403636
Let d = the distance from the station to the catch-up point.  Then from the formula t = d/r,
{{{d/125 - d/175 = 2}}} <==> {{{(2d)/875 = 2}}} {{{d/875 = 1}}}, or d = 875 miles.
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There is yet another way of approaching this problem, and that is to let 
t = time of travel of train 1 before the catch-up, and 
t - 2 = time of travel of train 2 before the catch,
and then use the formula d = rt, to get the equation 125t = 175(t-2).
But this is indirect...