Swiss Federal Railways has doubled its first-half loss to SFr36.6 million ($29 million) from SFr18.2 million in 2004 - despite carrying more passengers and goods.
The poor result was blamed on problems in the freight division, which is to shed hundreds of jobs, inadequacies in the pension fund provision, and falling government subsidies.
In a statement on Tuesday, the railways also attributed the increased loss to higher operating costs in the passenger sector and lower margins in goods transport.
The company said it had had to make payments of SFr66 million to shore up the employee pension fund.
It added that the need to further bolster the pension scheme would entail further costs and push the annual result into the red.
In 2004 the company recorded a profit of SFr42.6 million – its second annual profit in a row.
On the positive side, the number of kilometres travelled by passengers increased by 6.1 per cent to more than 6.5 million, with 11 per cent more customers using the busy Zurich to Bern route.
The railways said the new timetable introduced last year had led to an overall 7.5 per cent increase in passengers.
The company said the higher income resulting from the increase in passengers and freight "was not able to compensate for higher operating costs in the first half".
The railways' cargo division reported a 4.3 per cent drop in its first-half turnover to SFr477.8 million.
In a bid to reduce costs by eight per cent, it announced it would be cutting several hundred jobs out of a current total of 4,800.
The railways said profit margins had come under pressure as a result of increased competition in the sector.
While traffic on the north-south route increased by 22.2 per cent to 3.8 billion tons per kilometre, there was a 0.7 per cent drop in domestic cargo volume to 1,895 million tons per kilometre.
Unions have reacted angrily to the proposed job cuts. The association of Swiss railway and transport workers accused the federal railways of simply trying to make the figures look better. It said the situation in the cargo division was not as bad as was being made out.
The transfair union also questioned the need for more job cuts after hundreds of positions have already been axed in the division.
swissinfo with agencies
Every year Swiss Federal Railways transports over 253 million passenger and around 58 million tons of goods.
The railways network covers 3,000 kilometres. The entire Swiss public transport network covers 24,500km.
Federal Railways trains account for 87% of kilometres per person travelled and around 90% of goods transported in tons per kilometre.
The railways operates almost 800 stations serviced by hourly or half hourly trains.
In passenger transport Federal Railways recorded a 7.3% increase in turnover.
In the freight sector, turnover decreased by 4.3% to SFr477.8 million.
As a result, the cargo division now intends to cut hundreds of jobs.