Inside Analyzer, at the Schedule Main menu, at the Load Definition section of RM Bridge Enterprise we can find the Traffic Lanes input for Traffic Definition where a Lane macro can be used to interactively create several lines of Lane Loads with just one or some Lane macro input. The Live Load of the Load Train will be applied to this Lane Loads using the influence lines.
One common option is Traffic Lanes: Lane macro input - Loading Secondary girder & Distributed to main girder. As we can see in the screenshot below, this allow for using the Secondary girders as references when defining your model traffic lane. Using also the option Distributed to main girder will apply live load to the main girders using the cross-frames as references in the Lane Macro input. The difference of selecting or not is clear in the two images of RM Bridge Analyzer User Manual at page 150 in the image below. Another option that can be selected is the Orthogonal to lane option, and the difference can also be visualized in the images below.
More information can be found at the top meu Help\Application Help under the Traffic Lanes or at Help\Manuals\RM Analysis User Guide at Section 7.2.8.1 Lane Definition Traffic Lanes.
Similar application can be found at the Training Example for Grillage in the link below: