A very large part of the information contained in this blog is translated from the French.
Jose Banuado is the author of the book written in French about the tramways of Nice and the Cote d’Azur.  I have translated the part of that book which refers to the Great War with the help of internet-based translation software. His text is supplemented with additional information where available.
World War 1
In the fifteen years prior to the great War, the growth of the population of Nice and the surrounding towns and villages necessitated a rapid development of the tram network. The advent of the Great War prevented any further significant development of the network and by the end of the war, the network was in need of an in-depth modernization programme. However, it was not until 1924 that the authorities granted the TNL the authorization to increase tariffs.
During the War, a number of small schemes were undertaken with military needs in mind. Among other things, the network managed to obtain a connection to the PLM at the Saint Roch station and a connection with the Cannes tramways in the streets of Antibes. From July 1915, the laying of a TNL track to the new PLM station of Nice-St. Roch finally created a link between the two networks. In operation, this facility is used to ship the No. 7 Bogie Van required by the Military Authority for the Schlucht Line. (Photos -Jacques Schoffer – TCA Collection). 
Traffic decreased, especially that of tourists. The condition of the tracks was deteriorating, especially on the Monte Carlo line. Studies were undertaken to modify the lines of certain curves in order to admit bogie engines on the line, with the restoration of a few sections of track. This work was completed on 3rd September 1918.
Trams Serving the War Economy
The TNL was called upon to undertake a very important role in the national war effort and in supplying the region. As Nice was in a border zone, the arrangements for making tramways available to the military authority “in the event of a mobilisation, alert or unexpected attack” were established on 14 January 1910 by an agreement between the authorities in Nice, the TNL and the EELM company which was in charge of ensuring the electricity supply to the network.
From the day of the mobilisation, all the rolling stock assigned to the transport of goods (i.e. twelve tractors and one hundred and forty wagons) was made available to military. Within three days. 2110m of tracks were laid to connect the military establishments in the Riquier, St. Roch and Bon-Voyage districts, east of Nice, to the tramway network, to barracks, handling yards, subsistence shops and forage yards. An animal park was set up at the Var racecourse in St. Augustin, and a military training camp was created in the St. Véran district at the exit of Cagnes.
The tramways transported to these parks and warehouses nearly a thousand tons of food, military equipment and materials, ammunition and medicines, horses, mules, straw and fodder. Some of the supplies were unloaded at the port, often from the colonies. Other supplies arrived in Nice by the PLM, whose wagons transferred over a street connection in Falicon towards a transhipment platform in La Gare du Sud where a company of territorials, relieved every three hours, ensured day and night the transhipment onto the wagons of the TNL.
In the months following mobilisation, these military movements gave way in part to those needed for civil life: coal for the gas plant, wheat for the flour mills, goods for other French regions and even for Switzerland, etc. La Gare du Sud was heavily congested and in order to relieve that pressure and accelerate the transshipment of goods, the TNL, the PLM and the Chamber of Commerce concluded an agreement in March 1915, to establish a connection between the tramway to Contes and the new station at Nice-St. Roch, where a a series of sidings were created to facilitate transshipment. This installation, had a capacity of a thousand tonnes per day, was made operational in July. The following year, one lane was lengthened
to receive coal shipments to PLM locomotive depot nearby.In 1916, the connection of the trams to the PLM station in Nice-Saint-Roch was extended to establish a reserved lane for the unloading of English coal imported by sea. The TNL tractor No. 9 is pushing back a train of five high-sided open wagons containing coal onto this raised siding. The siding was 1.93m above its surroundings and over a good part of its length it was made up of scrap sleepers supplied by the PLM and simply stacked without any form of binding. (Jose Barnaudo Collection.)
The tramway workshop at boulevard Sainte-Agathe was one of the best industrial establishments of the city of Nice, and the military authorities took it over in January 1915 and conferred on the TNL the responsibilty for machining 75 mm shell blanks and training some 30 small businesses in the region to do this type of work. Manufacturing subsequently extended to 120 mm shells and small bombs. These small bombs were intended to be dropped by hand from aeroplanes. The raw materials were transported by railway from the Toulon arsenal to Nice, and the finished items were transferred in the opposite direction. Congestion on the PLM coastal line eventually led to these exchanges being undertaken by sea.
An abundant female workforce, provided in particular by the wives of combantants,
was used until 1917 in this war effort.
The depot of Sainte-Agathe also worked to transform wagons required on the other networks for by the 10th section of the military field railway. In 1916, the port of Nice received large shipments of American wheat which were removed by tramway to St. Roch station, the mill of Ariane and that of Monaco.Above, two trains for the needs of the Army during the 1914-1918 war: the first is No. 13 bogie tractor at the head of a train of straw or fodder at the depot of Sainte-Agathe. And the second, carries cars involved in an accident in a barracks. (Photos Jacques Schopfer – TCA collection.)
When more than one ship berthed at the same time, loads could not be moved by the TNL immediately. There was a lack of covered warehousing on the quays, so it was decided to convert the TNL depot at the port into a warehouse for the stacking of wheat. AS a result a storehouse for nearly 3000 tons of cereals in bags was created, which was still used by the civil supply administration for two years after the war.
The year 1917 saw tramway traffic increase in several areas. On 26 March 1917, after connecting the TNL and CTC tracks which until then had only crossed each other on the Place Jean-Macé in Antibes, a coal train was put into operation daily from the port of Nice to the gas plant of Cannes, located near Mandelieu. Since this service was entirely satisfactory and the PLM Marseille-Ventimiglia line was almost exclusively reserved for military transport to Italy, the tramway provided from 17 November 1917 an additional service. It transported cement from Contes to Mandelieu for the construction of the new military camp at Fréjus. When the cement arrived at the end of the Cannes network, cement was transshipped by trucks to a destination beyond the Esterel.
The wartime traffic made it possible to smooth out administrative difficulties between companies of the Nice and Cannes tramways, and even to silence the claims of the municipalities crossed for a tax on goods in transit!
Transport of the wounded.
From the first months of the conflict, most of the large hotels in the towns and cities of the Côte d’Azur had been requisitioned to house wounded and convalescing soldiers, war orphans and civilian refugees from the evacuated areas. The lines of the urban network of Nice as well as those of the coast which served these establishments experienced an intense traffic, increased from 1917 by contingents of Americans.
If for able-bodied passengers this influx only caused capacity problems, it was quite different for the transport of the most seriously injured who had to travel lying down. During the summer months, sixteen modified open trailers were used to transversely arrange ten stretchers. During the cold season, a tractor and eight vans were fitted out to longitudinally receive twelve stepped stretchers on three levels. If necessary, eight conventional urban power cars could each carry eight stretchers. Depending on the formation of the convoy and the gradients to be covered (many temporary hospitals were served by the steeply sloping Cimiez line), from 60 to 72 seated and lying injured people could be taken from the PLM station to the care and convalescent establishments.
There were twenty-eight such establishments in the city of Nice and its surroundings, these included the two mixed civilian and military hospitals of St. Roch and Villefranche, six auxiliary hospitals, ten additional hospitals, seven hospitals managed by volunteer staff and three convalescent centres, most of which were set up in requisitioned villas, residences and hotels. Their total capacity reached 7131 beds in care units and 1275 beds in convalescent homes, the numbers are mentioned in brackets in the following list.
- Eight establishments were served by the Cimiez line: École Normale (300 beds), Hermitage hotels (375, served by a private funicular railway). Regina (650), Majestic (650), Winter-Palace (400), de Nice (350). Riviéra (150) and Alhambra (162).
- The largest was at the terminus of the Imperial Park line: Imperial Hotel (800).
- Only one was served by the St. Sylvestre line: Parc Chambrun residence (280).
- Seven were located in the 1st town centre and served from avenue de la Gare or rue de Lépante: Hôpital St. Roch (275), clinique des Augustines (100), asile Evangélique (80), Grand hôtel (550), hôtels des Palmiers (350), Continental (575) and Gallia (300).
- Eight establishments were located on the Carras line: Lenval (65), Russian (24) and American (30) hospitals, Négresco (400), Ruhl (550), Royal (275), Ang1terre (175) and Palace (400) hotels.
- Three were located along the first line of Villefranche: English hospitals (60) and Villefranche (30), Villa Schiffanoia (50).
- Jose Banuado, Nice au fil du Tram, Volume 1; Les Editions du Cabri, 2004.
- http://transporturbain.canalblog.com/pages/les-tramways-de-nice—de-l-apogee-au-declin/31975780.html, accessed on 24rh August 2018.