In reading the book "Alexei Russia's Last Imperial Heir" by Margarita Nelpa has some vehicle info: It mentions in September 1914 an ambulance column attached to the Northern Front having 7 ambulances 5 Russo-Balt modified by Adolphe Kergesse and 2 Renaults with "truck snow gear". They were marked "Tsarevich Alexei" as was the hospital train he sponsored. Alexei also had a 1912 model Renault Bebe the first child's car bought for him by his father the Tsar. After WW I it was put on display in the then Leningrad Pioneer palace and destroyed in a 1942 bombing raid.
In Kergesse's wiki bio is a picture of one of Lenin's Rolls-Royce Silver Ghosts fitted Kergesse tracks for those of you who want to build the resiresco kit of it in 1/76 scale see tinsoldier.com