Sonic Mach number (upper panel), normalised CR pressure (middle panel), compression ratio and factor proportional both to E_esc,d and E_loss for parallel shocks (grey and black lines, respectively, in lower panel) as a function of the temperature for x = 0.3, η = 10^-5; U = 40 km s^-1 (solid lines), U = 80 km s^-1 (dashed lines), U = 120 km s^-1 (dotted lines), and U = 160 km s^-1 (dash-dotted lines).