  Directed flow of neutral strange particles in heavy ion collisions at AGS is
studied in the ART transport model. Using a lambda mean-field potential which
is 2/3 of that for a nucleon as predicted by the constituent quark model,
lambdas are found to flow with protons but with a smaller flow parameter as
observed in experiments. For kaons, their repulsive potential, which is
calculated from the impulse approximation using the measured kaon-nucleon
scattering length, leads to a smaller anti-flow than that shown in the
preliminary E895 data. Implications of this discrepancy are discussed.

Nuclear Theory