...or to put it another way: how to boost the pulling power of the Athearn Mikado and improve its over-all performance. If this subject is of interest to you, please read through before starting: while not particularily difficult, it involves working with lead, so if you're uncomfortable with this, save your time. The gain is dependent upon addition of lead. The first step is to disassemble the locomotive, making notes and/or sketches as required, to aid in re-assembly. First, disengage the boiler braces from the sides of the smokebox, then remove and discard the long screw that goes up through the cylinder block. Disengage the lower ends of the cab handrails, and then, using a small flat screwdriver, carefully spread, from the inside, the bottom front corners of the cab, and lift off the cab. Next, squeeze the lower rear end of the boiler between your thumb and forefinger, in order to disengage the tabs that protrude through the firebox, then lift. Continue lifting the rear of the boiler until it is high enough to clear the top of the motor (this is a tight fit). Now slide the boiler forward until it clears the front of the main boiler weight, and set aside. To remove the weight/motor/idler gear unit, remove the screws from both sides of the boiler weight (above the lead driver), and the screws from the motor terminals (bottom rear area of the motor). Lift off the entire assembly, feeding the "pigtail" through the slot at the rear (the small circuit board on the end of the pigtail must be removed to obtain enough clearance). Now, slide the running board/lower boiler assembly to the rear, until the protrusion on the chassis is clear of the slot in the lower cab backplate. Lift off, and set aside, taking care to not lose the screws. To disassemble the weight, remove the three screws (and nuts) as shown in the photo below. Don't lose the plastic spacers from between the halves of the weight. Carefully separate the two parts of the weight: the motor and driveline should stay together with one side or the other. If you are using DCC, or want working lights but don't wish to rewire them, skip this step. I feel that the "pigtail" adversely affects the tracking qualities of the tender, so I remove it. To do so, strip the heat shink tubing from the wires and cut the Red and Black wires near the circuit board. Unsolder the Grey wire from the upper motor terminal and replace it with the bare end of the shortened Black wire. Repeat this operation, using the shortened Red wire to replace the Orange wire on the lower motor terminal. On re-assembly, the brass terminal connectors on the other ends of these wires will be screwed on at the rear of the motor as before, Red on the right (engineer's side), Black on the left (fireman's side). Mark the top of the motor, and note the placement of the worm bearings and the idler gearbox. Remove the motor/flywheel/worm/bearings as a unit and set aside. Remove the idler gearbox. Wipe the stripped-down weight halves of excess grease and oil. Using a suitable square, and working on the inside face of each half weight,project a line from the forward face of the gearbox protrusion up to the top edge of the weight, then carry this line onto the outer surface of the weight. Using a suitable straightedge, line it up with the top edge of the two bearing retainer slots machined into the casting. Scribe or mark a line from the previously scribed vertical line, forward to the end of the flat surface. The arrows on the photo indicate the bearing slots. Scribe another vertical line mid-way between the hole for the front screw/spacer/nut and the square depression machined into the bottom of the weight, which accepts the mounting protrusion that extends upward from the chassis. This line represents the first cut, which will remove the shaded area in the photo.