[LEAD]The Korean Railway Workers' Union and Seoul Metro Union workers are currently conducting a 'work-to-rule' protest. The railway union has declared a general strike on December 5th if negotiations fail. The Seoul Metro Union has also announced a strike, potentially causing major year-end rail service disruptions.[REPORT]The Korean Railway Workers' Union has been waging a 'work-to-rule' protest for four days.Passenger inconveniences were reduced as the delay rate of subway trains in the capital area during commuting hours fell from 18% on the first day to 3%.The unionized rail workers announced that they will go on a general strike on December 5th if negotiation breaks down.Choi Myeong-ho/ Chief, Korean Railway Workers’ UnionWe plan to go on an indefinite general strike on Dec. 5 to restore trust safety standards in the workplace and to protect workers' rights.The key issues are a 2.5-percent increase in base salary, implementation of a four-team, two-shift system, and labor reduction by 1,500 workers.Striking a deal doesn't look easy as these issues can be better resolved by the transportation ministry rather than railway management. If the railway union launches a strike, KTX and regular trains run by the Korea Railroad Corporation and the subway services in the capital area are expected to be provided at a 70% capacity of normal operations.Korail said it will continue talks with the union until the last possible minute and when the strike becomes inevitable, an emergency transportation headquarters will be set up to pull all available resources to minimize passenger inconvenience.Concerns mount over simultaneous subway service disruptions during the year-endas the labor union representing Seoul Metro workers responsible for running subway lines one through eight in Seoul has also announced a full-scale strike on December 6th.