Your in a warm climate. CN deals with this every year. I owned a business in Wisconsin and had great service and a working relationship with SOO, CNW and WC when they came. When CN took over things got awful and I sold the business which in turn moved it out of CN territory. I have many friends who worked for CN and they are big on big trains and small power and tight schedules. My son worked for the WC and then after 2 months of CN switched to UP. When WC had cold temps they shortened trains and added mid train helpers to keep the pressure up, I do not know the length of train involved or loco placement. I am not blaming CN but I will not be surprised if they are found at fault.