Lima XPT/HST Re-Powering Conversion Please read through these instructions before beginning the conversion process. Non-Powered Bogie The front non-powered bogie is the starting point for this conversion. Remove the body shell by un-screwing the two central screws underneath the chassis. Unclip the electrical connection to the front bogie, and it should fall out of the chassis. Using a small bladed screw-driver, release the two clips, fore and aft that retain the bottom keeper plate on the bogie, indicated by the white arrow in the photo below. Remove the keeper plate and the wheels should simply fall out of the bogie. Take care the central spring loaded pin does not fly away. Carefully clean the brass axle wiper plate where it was in contact with the original axles, using a fibre glass pen or fine sand paper, this plate will be used again.

You should now have a bare moulded bogie frame with nothing else attached. Strictly speaking, it does not matter which side of the bogie the next step is performed, but for the sake of uniformity, we will opt for the right side of the bogie as viewed from the driver’s position. There is an actual front and back to the HST bogies, the front being the end that has the guard irons moulded into the side-frames. These are projections that stick out and downward at the front of the bogie, indicated by the red arrow in the photo above.

Drill a 1mm diameter hole in the side of the central section, on the right hand side, as shown in the photo. The hole needs to be in the centre length wise and 3.5mm down from the top. Note that the side-frames can be bent down quite a lot to get them out of the way during this process, they are very flexible. In the photo a pair of vice grips was used to hold them down while drilling.

Test fit the small supplied 1.4mm self-tapping screw into the hole. Take the supplied pickup device with wire attached, and cut 3mm off the ends of the two wipers, they are just a fraction too long. Screw the wiper into position with the self-tapping screw as shown in the photo. With a pair of side-cutters, cut off the part of the self-tapping screw that protrudes into the middle of the inside cavity of the bogie. This is to prevent it shorting to the Lima wiper unit.

Re-install the Lima axle wiper unit and place the supplied replacement wheel sets into the slots in the bogie frame. Take care that the insulated wheel is on the side that the newly fitted pickup is located. You can identify the insulated wheel by the black plastic ring visible on the outside surface, between the axle and the wheel. Insert the spring loaded pin into the wiper and bogie frame. Push the spring down, and hold it with two fingers, in the compressed position, while re-installing the plastic keeper plate over the wheels.

Turn the bogie over and insert a blade behind the wiper arms and gently bend them outwards as shown, such that they wipe lightly against the inside of the wheels.

Using a twist drill between 1 and 1.5mm in diameter, drill a hole in the locomotive chassis to the right of the front bogie mounting hole, as shown in the photo below. Re-fit the front bogie, passing the red wire up through the hole you just drilled. Fit the clip retaining the bogie to the chassis.

Power Bogie From the underside of the chassis, remove the two screws at the front and rear of the Lima power bogie. The power bogie can then be removed from the chassis and put aside. The original side frame and coupler attachment will be used again, but we need to perform some serious surgery on it to fit it over the new BullAnt power bogie. Cut through the bogie in the places indicated by the white arrows and as close to the red lines as possible, as shown below.

Note that it is best to leave a bit of plastic at the coupler end by cutting just to the inside of the screw hole. Also, cut off the mountings lugs that protrude above the bogie side frames. This is best done with a really sharp blade. The plastic material is soft and easily cut.

The following photo shows the unnecessary parts removed from the frame. However, there are two wedge shaped sections that must be shaved off the side frames, as indicated by the white arrows. These will get in the way of the attachments to the BullAnt.

The existing side frames of the Lima model are made from a particular plastic that we cannot glue easily to, probably Acetal or better known as Delrin. It is therefore necessary to make up two ‘transition’ plates of styrene that can be screwed to the side frames, and then the BullAnt bogie can be glued easily to those plates. From the supplied 30 thou plastic card, cut two pieces 6.5mm x 14.5mm in size (Part A). Refer to the cutting diagram at the end of this document to identify the parts. The preferred method for cutting styrene is to score and snap. Mark out the size with a sharp blade on the styrene then bend and snap off the section. Drill two holes 1.5mm diameter approximately 1.5mm in from each end in the centre. Hold one of these drilled pieces against the inside of the Lima side frame, mark the hole positions and then drill short pilot holes in the side frames with a 1mm diameter drill. Do not drill these holes very deeply, or in other words, avoid drilling right through and out the other side of the frame. Take the four remaining self-tapping screws and cut approximately half a millimetre off the end of each one using a pair of side-cutters. They need to be shortened slightly so as not to protrude through the other side of the side frame. Screw the two pieces of styrene to the inside of the side frames as shown below. Cut two smaller pieces of the 6.5mm wide styrene (Part B), approximately 10mm long, or enough to fit snugly between the screw heads, as shown below. Glue these to the screwed down pieces using styrene glue or MEK.

Turn the BullAnt bogie upside down and stand it on the nickel silver mounting bracket. Place a suitable packing piece under the flywheel to make it stand stably. Cut two small pieces of the 6.5mm wide styrene to act as temporary packing pieces (Part C), and place them on top of the nickel silver mounting, as indicated by the arrow below.

Place the Lima side frame upside down onto the BullAnt, and carefully align it so the wheels are equi-distant from the frame, and the axles in the BullAnt line up with the centre of the axle boxes on the Lima side frame. Take some time and care with this step, in order to get the best fit possible. Please note the arm of the coupler mounting is at the same end of the BullAnt as the flywheel.

As we are about to glue the side frames to the BullAnt, please check everything is in the correct position before applying glue. Use whatever packing devices you need to set all parts in the right place. You may need to put a support under the back end of the coupler tongue so that it does not droop down at that end.

When and only when, you are happy everything is correct, use a small brush to dribble some MEK or other liquid glue down between the white styrene plates on the side frames, and the ends of the black BullAnt pickup bolsters. The correct spot is indicated in the photo above by the two arrows. Leave this assembly overnight to set. This is important, as it needs to be solidly glued before proceeding with the next part of the conversion. Once set, the temporary packing pieces can be removed. Lima Chassis Modifications The main chassis of the model now needs some modifications to fit the BullAnt. There are two small lugs the project out into the interior of the model, and they need to be cut off. Cut along the line shown in the following photo. Take care cutting these off, the material is styrene and not as tough or flexible as the side frames. Shave these lugs back until they are flush with the inside edge. Leave the raised rails as these are required.

Cut four strips of styrene from the piece provided, 20.5mm x 17.5mm. Using a liquid glue, laminate pairs of these together to form two panels 60 thou thick (Parts D).

When the glue has set sufficiently to handle the panels, drill a 2mm diameter hole in each panel in the position shown in the drawing. Glue these panels to the inside of the Lima chassis, sitting on the stepped up rails, as shown in the drawing.

Make sure the hole in the panels line up with the raised bump on the outside of the chassis, as indicated by the white arrow in the photo above. Unclip the rear tank assembly from the main chassis at the clips shown by the red arrows above. The two sections that protrude forward need to be trimmed off, at the point shown by the red lines in the photo below. Once trimmed, clip the tank assembly back into the chassis.

Place the BullAnt power bogie in the chassis, and secure it with the supplied 2mm screws and nuts. To ensure the bogie does not move about, cut four pieces of styrene, 6.5mm x 17.5mm long, and cement them either side of the nickel silver BullAnt mount. These pieces are indicated by the red arrows in the photo below (Parts E).

Bring the two wires, red and black, forward from the front non-powered bogie. Place the metal weight back in the chassis fuel tank area and route the wires either side of the weight. Allowing a small amount of slack for the front bogie to rotate, solder the wires to the connection tabs on the BullAnt bogie. Red wire should be on the same side as the red wire on the BullAnt. If this is not the case, then possibly you have mounted the additional pickup on the wrong side of the bogie, or the bogie is the wrong way around in the side frame. The finished conversion should look something like this:

Replace the body shell onto the chassis, and fasten in place using the original screws. Test run the finished model. Styrene Cutting The following diagram shows how to cut the various parts out of the piece of supplied styrene sheet.

Maintenance The BullAnt power bogie will require occasional lubrication, but this does not need to be done very often and MUST be done sparingly. Over lubrication is the most common cause of power bogie problems. A drop of light oil, such as LaBelle 108 should be applied to the brass axle bearings. There are four of these, located on the axle inboard of each wheel. They are just visible inside the black plastic axle housing. A small amount of Teflon bearing grease can be inserted through the rectangular hole in the axle housing. DCC Considerations The BullAnt power bogie can be used with a 1 amp decode. Isolating the pickups only requires disconnecting the red wires and black wires from the motor. The red wires connect to the red wire from the decoder, and the same for the black.