/* -*-ePiX-*- */
#include "epix.h"
using namespace ePiX;

double mA(-1), mB(1), mM(0), dx(0.5), dy(0.1);

void veloc(const P& loc, const P& off,
	   const std::string& msg, epix_label_posn A)
{
  arrow(loc, loc + P(dx,0));
  label(loc, off, msg, A);
}

int main()
{
  picture(P(-2,-0.25), P(2,0.25), "4 x 0.5in");

  begin();
  bold();
  arrow_inset(0.5);
  arrow_ratio(2);
  arrow_width(2);

  line(P(xmin(), 0), P(xmax(), 0));
  line(P(xmin()+0.25, dy), P(xmax()-0.25, dy));
  line(P(xmax()-0.25, dy), P(xmax()-0.15, dy + 0.1));

  h_axis_tick(P(mM,0));
  h_axis_tick(P(mM,dy));

  tick_size(6);
  h_axis_tick(P(mA,0));
  h_axis_tick(P(mA,dy));

  h_axis_tick(P(mB,0));
  h_axis_tick(P(mB,dy));

  veloc(P(xmin()+0.25, 2*dy), P(2,2), "$v$", tr);
  veloc(P(mB+0.25, 2*dy), P(2,2), "$v$", tr);
  veloc(P(mM+0.125, 3*dy), P(-4,0), "$M'$", l);

  label(P(mA,0), P(0,-10), "$A$", b);
  label(P(mM,0), P(0,-10), "$M$", b);
  label(P(mB,0), P(0,-10), "$B$", b);

  label(P(xmax()-0.15, dy + 0.1), P(4,0), "\\textit{Train}", r);
  label(P(xmax(), 0), P(-24,-8), "\\textit{Embankment}", br);

  tikz_format();
  end();
}