<p>The mathematical analysis is presented for calculating the film thickness at the contact center in the hydrodynamic lubricated rolling and sliding steel line contact with the equivalent contact radius on the scale of 100mm by considering the contact thermal and macroscopic elastoplastic deformations where the film thickness is ultra low so that the adsorbed layer-continuum fluid-adsorbed layer sandwich film occurs in the inlet zone and the non-continuum physically adsorbed molecule film occurs in the flattened contact area. The calculation was made for widely varying heavy loads, slide-roll ratios and contact hardness. It was found that the lubrication in the studied contact is qualitatively different from the classical elastohydrodynamic theory description in the condition of very low film thicknesses. The effect of the adsorbed layer makes the film thickness maintained even only with several fluid molecule sizes but much higher than the classical elastohydrodynamic theory calculation. The strong contact-fluid interaction yields the significantly higher film thickness than the weak or medium contact-fluid interactions. Both the increase of the slide-roll ratio and the reduction of the contact hardness rapidly reduce the central film thickness owing to the contact thermal and plastic deformations. The variations of the lubricating film thickness at the contact center with the rolling speed and load no longer follow classical elastohydrodynamic theories because of the strong effects of the adsorbed layer and the contact thermo-elastoplastic deformations. For heavy loads, high rolling speeds and appreciable slide-roll ratios, the effect of the contact thermo-elastoplastic deformation not only largely reduces the central film thickness but also greatly increases the sensitivity of the central film thickness to the load variation.</p>