I am sure I am not the first to encounter what I fondly call "End game Assassins". The purpose of the EG assassin is to create rail connections with all the EG cities so they can locate one or more engines in those cities for the purpose of transporting goods from all the RG's of the city and eliminate the 0:00 w/t for a completely cooled down factory. One train can successfully carry 4 or 5 RG's in a schedule to accomplish this rather nefarious EG tactic. If you use this tactic can you truly claim the First Place honors without actually out-hauling your opponents or maybe you just want to claim the pp without doing the hard work of coordinating a team of associations in your city. I propose the following possible solution:
Servicing engines is required to maintain your engines in a peak performance state. In the real world of locomotives that would require that the engine to be brought to the maintenance facility for the work to be done. In the imagined world of RN the servicing is magically done by just paying the costs of service. I propose something along these lines. Each engine must periodically enter the home city train station (travel through the home city) of the player for maintenance purposes. Let's say the engine frequency is every 3 days. The closer an engine gets to that deadline the faster they lose their maintenance reliability until the 72 hours expire and then the engine would automatically return to the home city (at a reduced service % - like 10% or higher if the player pays emergency maintenance costs to increase it to a top of 50%). Some other possibilities could be 1) Pax trains could be exempt or have a longer frequency before the maintenance stop is required. 2) The longer the time away from the home city, paying for maintenance on the engine would accomplish a lower performance percentage. 3) A bonus "maintenance engine" could be purchased or won (later eras) that can travel to the engines and perform maintenance resetting the clock for the engine. 4) Mechanics cannot be hired for an engine that has been away from the home city over a set period of time (like 24 hours). 5) During era 6 and End Game maintenance requirements would become more frequent and losses of performance percentage would be accelerated. Also severe limits on changing the home city would be established.
So, just some ideas that would add a wrinkle to maintaining engines and hopefully lessen the effects of End Game Assassins!!