The Q-function of the quantum soliton in a fibre is derived in a new form s
uitable for the assessment of the possibilities for experimental observatio
ns of specific quantum-soliton effects. The characteristic effects of solit
on evolution are associated with a cubic term in the nonlinear phase angle
and appear at distances well beyond the attenuation length (long range). At
the accessible distances, the nonlinear dynamics of a fundamental soliton
follows essentially the single-mode dynamics (short and middle range). Howe
ver, for the higher-order solitons, the form of the evolution parameter sug
gests strong deviations of soliton dynamics from the single-mode with a squ
are of soliton number. The use of enhanced-nonlinearity fibres and higher-o
rder solitons might make the experimental studies of the specific quantum-s
oliton features more viable.