EMD's are a different story. They have very high starting tractive effort, but will start degrading in performance compared to the WAPs beyond 25-30kmph. So, they can start heavier loads, but can only run at low speeds with them. Their capacity at high speeds is also limited.
Push-Pull EMD would also be a good option, preferably with the WDP4 locos, more than the 4D or 4B.