CSX uses road slugs (2200-2350), old GP30 and 35;s here in south central Pa over the mountains from Hagerstown Md to York Pa. How are they rigged differently since yard slugs run at low speed and road slugs do not. When they pass throught Gettysburg, I watch them and they are running at up to 45 MPH.
Yard slugs are typically wired in series with their mothers. Voltage limits on the main generator limit top speed to half of normal. You have to come to a stop and cut out the slug if you are planning to operate at normal mainline speeds. Yard slug are typically used to increase tractive effort and braking only and do not have fuel tanks or operator’s cab.
Road slugs are designed to automatically cut themselves out at speed. They do this by shunting the traction motor armature (field windings) at a pre-set speed (around 25 mph). The CSX road slugs also retain their cab, fuel tank and dynamic braking.
Do you mean by “Shunting the tractive motor armatures” that they do not draw any power over 25 MPH?