Lubricating oil compositions for railroad diesel engines

A method for inhibiting wear of silver wrist-pin bearings in a two-cycle railroad diesel engine which method comprises lubricating the internal portion thereof with a lubricating oil composition which consisting essentially of:

• a single or multi-grade oil of lubricating viscosity;
• a sufficient amount of a calcium overbased sulfurized alkylphenate composition so that the total base number in the lubricating oil composition is from about 5 to about 30;
• and
• a wear-inhibiting amount of at least one lubricating oil soluble and compatible compound selected from the group consisting of compounds of formula I
• R--X--[(R.sub.1 O--).sub.n H].sub.m I
• of formula II ##STR12## of formula III ##STR13## and products obtained by reacting the compounds of formula II and III with from 1 to 30 equivalents of a compound selected from the group consisting of alkylene oxide of from 2 to 6 carbon atoms, glycidol and mixtures thereof under conditions resulting in formation of an alkylene oxide and/or glycidol adduct of the compounds of formula II and III
• wherein R is a hydrocarbyl radical having from about 4 to about 50 carbon atoms;
• R.sub.1 is independently an alkylene group of from about 2 to about 6 carbon atoms;
• X is selected from the group consisting of oxygen, sulfur and nitrogen;
• n is an integer from 1 to about 30 m is 1 when X is oxygen or sulfur and is 1 or 2 when X is nitrogen;
• and
• with the proviso that when R.sub.1 is ethylene, then the oil of lubricating viscosity is a single grade oil.