Railroads hate double ended pools because of the cost, miles balancing,claims for mishandling and the difficulty in managing these pools.Double ended pools are often ,if not always the product of terminal run-throughs where the away from home terminal has been eliminated in favor of retaining the home terminals that formerly ran into the away from home terminal.Increased miles resulting in these run-throughs results in more time at home because of fixed mileage regulation.I have worked all of these types of pools and could comment furher ,but I will stop here.