Run through power on the Sunset route is not new. I ran "foreign" power in consists on the Yuma pool many times Very often these days, foreign power can be seen on many run through interchange trains. This also results in UP or BNSF power ending up in Pennsylvania or Georgia on CN, NS, or CSX lines. Sometimes foreign units can be leased power, used to meet short term power needs. I've also noticed "unmarked" leased power from independent locomotive lessors supplementing power needs.