These Pullman "Type 43" triple-bolster wing-box trucks were used on Southern Pacific's lightweight Daylight passenger cars of the 1930s and 1940s. Similar trucks were used under ATSF, NYC, PRR, and UP Pullman cars, as well as under a number of Pullman lease cars. Their nickname - "Napoleon Hat" - derives from the distinctive bell shape of the journals.
The trucks used on the original 1937-1939 Daylight had solid bearings and no bolster anchors. The trucks used on the 1941 Daylight were upgraded to include bolster anchors; 4-TCA-3/43-A-11 under the articulated chair cars, 6-TCA-1/62-A-11 under the articulated diner cars, and 4-TC-7/43-C-11 under all the rest. Post-war, the solid bearing journals were upgraded to roller bearings.
Kato makes Daylight trucks that are modeled after the 1941 prototypes. These are available in three different styles -
4-TC-7 - Kato catalog #800105 (SP Daylight Truck with Coupler, 1 ea)
4-TC-7 - Kato catalog #800107 (SP Daylight Observation Truck w/o Coupler, 1 ea)
6-TCA-1 - Kato catalog #800106 (SP Daylight 3-Axle Articulated Truck, 1 ea).
4-TCA-3 - Kato catalog #800108 (SP Daylight 2-Axle Articulated Truck with Diaphragm and swing Bar assembly, 1 ea).
Note that the articulated trucks do not provide electrical pickup. They have different wheelsets (longer axle points) and lack copper bearing-cup plates (IE, the axle ends cradle directly into the plastic sideframes).
Des Plaines Hobbies also makes 2-axle and 3-axle truck kits in this style (for use on their four-truck Triple Diner kit) -
Lastly, Shapeways designer "Susquehanna Car Shops" makes a similar truck (which they designate as Type 43-R) that may be more appropriate for non-SP applications -
800105/800107/800108 Wheel Diameter 0.220" (scale 36")
800105/800107/800108 Wheelbase 0.680" (scale 9')
800106 Wheel Diameter 0.220" (scale 36")
800106 Wheelbase between outer axles 0.871" (scale 11' 7")