The trucks on the ICG's ex-GM&O GP-30's and GP-35's were from Alco FA/FB trade-in's. The Alco four-wheel swing bolster trucks with the special Alco lever pin and retainer at the pull rods were rebuilt at EMD, which also rebuilt the GE Model 752 traction motors to their (GE's) specifications. The original GE 74:18 gear ratio was retained due to the large center distance between the 752 armature shaft and axle. This gear ratio provided a maximum speed of 71 mph. All units were equipped with dynamic brakes. The GM&O obtained a total of 48 GP-35's from EMD in 1964-65.

South of Venice, Illinois, the GM&O was what might be called a 'drag railroad', with trains run at or near full tonnage. Between Venice and the Ohio River, the tonnage rating in both directions was set by a hill called Alto Pass. Although Alto Pass was not very high or long, it was steep, and included a number of curves. The railroad expected to hang everything but the kitchen sink behind the new GP-30's and GP-35's and crawl up Alto Pass. During the years 1963, 1964, and 1965, the railroad and EMD conducted many wheel slip tests in drag freight service on the hill. The somewhat different electrical characteristics of the 752 traction motor and the ride response of the AAR Type B trucks required a number of modifications to the wheel slip systems in order to obtain maximum tonnage over Alto Pass. Trotting along side of the lead GP-30 of a four unit consist climbing Alto Pass, moving under five miles per hour in 8th throttle, in order to watch the slipping lead axle is not recommended practice, but it was done in the interest of 'science'. Alto Pass has been abandon now in favor of the more gentle grades on the old passenger main line of the Illinois Central just a few miles to the east.