The electromagnetic two-body problem must be solved as a variational boundaryvalue problem because it is not a semiflow on C 2 (R). In order to allow forward integration by the method of steps, we generalize electrodynamics by adding another time-reversible interaction along lightcones. The equations of motion are time-reversible and define a flow on C 2 (R) with four state-dependent delays of neutral type and nonlinear gyroscopic terms. The flow includes an inversion boundary layer where attraction turns into repulsion. Moreover, the forward propagation of velocity discontinuities requires two additional constraints; the energetic Weierstrass-Erdmann conditions, which define the boundary layer neighborhood where velocity denominators become small. In order to display the boundary layers in the simplest form, we discuss the motion restricted to a straight line by the initial condition.