Sandwiched Locomotive

A rather unusual train arrangement seen on 2218 (MD-W) this morning. I had just arrived at Roselle for 2220 when 2218 (no stop at Roselle) passed through. The usual four cars, the locomotive, and then a cab car being towed! Must have been bad-ordered and they decided towing it in was the best move. It was sitting on Track 1 at CUS when I arrived on 2220 (I believe it normally turns to 2209 on a different track). I wonder which train was short a car this morning.