What type of spikes are required for rail braces?

The correct answer is screw spikes, as they are specifically designed for securing rail braces. Screw spikes provide a strong and durable connection, which is crucial for maintaining the stability and integrity of the rail structure. They are often used in applications where a firmer hold is required, as they can resist loosening due to vibrations from passing trains and environmental factors. This makes them an ideal choice for attaching rail braces that support the alignment and strength of the tracks.

The other options, though they have their uses in rail construction, do not fit the specific requirement for rail braces. Nail spikes, for example, are generally used for fastening wood ties or other non-load bearing applications. Rail spikes, while important for attaching rail to ties, do not provide the same strength or resistance to loosening as screw spikes in this context. Wooden spikes are largely outdated for modern rail applications and are not typically used in current construction practices due to their less reliable performance compared to metal options.