#583 Arch Bar Caboose Trucks "HGC" Two Piece Fully Equalized Self Centering Trucks Truck Features • Code 110 (.110 wide) 33" ribbed back "standard" wheels • "HGC" High Gravity Compound Weighs nearly the same as Metal Trucks • Self-Centering • Superior Rolling Ability. • Brake Pads • Accurate markings • Incredible detail True to prototype • Non-magnetic Metal Wheels • Highly Flexible Fully Equalized Trucks • Smooth tracking Free rolling Contoured Insulated Axles • RP-25 Free rolling wheels Package Includes: (2) Each #583 Arch Bar Self Centering Caboose Truck (Leaf Spring) (assembled) (2) Clip on Brake Pads (2) Each Self Centering Bushing (2) Each #2 Screw The term Code 110 and Code 88 relates to the width of the wheels and has no relationship to track code. Code 110 wheels are .110" wide and Code 88 are .088" wide. Code 110 wheels are the common (or "Standard") width wheels and Code 88 are what is called "Semi-Scale" and are used when the modeler wants a more prototypical looking wheel width. Actual HO-Scale prototypical wheel width would be around .067" wide and although they will run OK on the average track they will not go through common turnouts and crossings. Code 88 (.088") is just about the minimum width of wheel that will run on most standard or common track if gauged correctly. It really is a matter of appearances because there's very little operational differences between running Code 110 or Code 88 wheels. Code 88 wheels look really good and are most noticeable on open frame cars like hoppers and tank cars. However, they also look great on boxcars, gondolas, and reefers but not quite as noticeable. As mentioned above track code and wheel code have no relationship meaning Code 110 and Code 88 will run on most any code of track. Track code is simply the measured height of the rail, code 100 is .100" tall, code 83 is .083" tall, code 70 is .070" tall, and so on.