Caption: A rare newly built Tier 3 unit. CN 529 with 32 cars is through Montreal West with an interesting leader. NS 8168 is just one of three Tier 3 compliant ES44AC's built for NS a couple of months ago (NS 8166-NS 8168). While NS, like most North American Class I's is primarily receiving Tier 4 ET44AC's, the three new ES44AC's were allowed due to GE applying emission credits that had already been banked towards them. Trailing is a much older GE, ex-Conrail NS 8445 (built in 1994). Both units were built at the Erie plant.